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Classifications

Harrison's Part

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Definitions

1

CDC clinical case definition for toxic shock syndrome

The US Centers for Disease Control and Prevention case definition for staphylococcal TSS requires fever, a diffuse macular erythroderma, desquamation one to two weeks after rash onset, hypotension, and involvement of at least three organ systems from the gastrointestinal, muscular, mucous-membrane, renal, hepatic, hematologic and central nervous system categories. Because desquamation appears only during convalescence, a confirmed case is often only assignable retrospectively, which limits the definition's usefulness at the bedside.

CASE_DEFINITION

Show evidence (2 references)

PMID:31151811 SUPPORT Human Clinical

"The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement)"

Enumerates the five CDC clinical criteria that constitute this case definition.

PMID:31151811 SUPPORT Human Clinical

"the CDC criteria have appreciable limitations in everyday clinical practice."

Supports the recorded caveat that the case definition, designed for surveillance, performs imperfectly as a bedside diagnostic instrument.

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Subtypes

2

Staphylococcal toxic shock syndrome MONDO:0020545

Toxic shock syndrome caused by Staphylococcus aureus superantigens, classically toxic shock syndrome toxin-1 (TSST-1) and the staphylococcal enterotoxins. It is subdivided clinically into menstrual TSS, historically linked to high-absorbency tampon use, and non-menstrual TSS arising from surgical wounds, burns, nasal packing, or postpartum infection. Case fatality is substantially lower than in the streptococcal form.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Staphylococcal TSS can be menstrual or nonmenstrual."

Supports the staphylococcal subtype and its menstrual/non-menstrual clinical division.

Streptococcal toxic shock syndrome MONDO:0020544

Toxic shock syndrome caused by Streptococcus pyogenes superantigens, principally the streptococcal pyrogenic exotoxins and streptococcal superantigen A. It arises in the setting of a severe invasive group A streptococcal infection, most often a necrotizing soft tissue infection, and carries markedly higher mortality than staphylococcal TSS.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Streptococcal TSS is linked to a severe group A streptococcal infection and, most frequently, to a necrotizing soft tissue infection."

Supports the streptococcal subtype definition and its characteristic association with invasive necrotizing soft tissue infection.

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Discussions and Knowledge Gaps

1

Does adjunctive intravenous immunoglobulin reduce mortality in streptococcal toxic shock syndrome?

CONTROVERSY OPEN ivig_mortality_benefit_tss

Attached to

pathophysiology#Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking

The mechanistic rationale is strong and specific: pooled donor immunoglobulin should neutralize circulating superantigen and so interrupt the MHC class II/TCR bridging step this entry models as the initiating molecular event. The clinical evidence does not settle the question. A systematic review and meta-analysis restricted to clindamycin-treated streptococcal TSS reported mortality falling from 33.7% to 15.7% with consistency across one randomized and four non-randomized studies, whereas a Japanese nationwide observational study of 481 patients with invasive group A streptococcal infection found no effect on in-hospital mortality after adjustment or after propensity-score matching. The two are not straightforwardly comparable: the positive estimate is conditioned on concurrent clindamycin and confined to streptococcal TSS, while the null result covers invasive group A streptococcal infection broadly, and its own authors caution against extrapolating to streptococcal TSS. Disease rarity makes an adequately powered randomized trial difficult. The treatment entry therefore carries both a SUPPORT and a REFUTE evidence item rather than a single adjudicated verdict.

Show evidence (1 reference)

PMID:37586661 SUPPORT Human Clinical

"However, these overall findings should not be extrapolated to streptococcal toxic shock syndrome as the effect of IVIG therapy in this condition remains uncertain."

The null-result authors themselves state that the effect in streptococcal TSS remains uncertain, which is the open question recorded here.

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Pathophysiology

11

Absent or Low Neutralizing Antitoxin Antibody

Most adults acquire neutralizing antibody to TSST-1 through subclinical colonization. Individuals who lack such antibody at the time of toxin exposure are unable to neutralize the superantigen, and this deficit is the principal recognized host susceptibility determinant for staphylococcal TSS. Antibody levels are strongly determined by both the degree of colonization-driven toxin exposure and HLA class II genotype.

humoral immune response GO:0006959 ↓ DECREASED

Downstream

Superantigen Exotoxin Production Without neutralizing antitoxin, secreted superantigen reaches its host receptors and initiates the disease cascade.

Show evidence (3 references)

PMID:6491377 SUPPORT Human Clinical

"The data suggest that absence of antibodies to the TSS toxin may be a predisposing factor in the development of clinical disease."

Case-control serology showing antitoxin levels are significantly lower in women with TSS than in controls, supporting absent antibody as a predisposing host factor.

PMID:37731490 SUPPORT Human Clinical

"A well-known risk factor is the lack of neutralizing antibodies."

Population-based study confirming lack of neutralizing antibody as the recognized risk factor this node represents.

PMID:20036064 SUPPORT Human Clinical

"Children are at risk of developing staphylococcal toxic shock syndrome when their immune system is immature and they have no protective circulating anti-TSS antibodies."

Age-stratified serology showing risk tracks the absence of circulating antitoxin, with maternally derived antibody protecting infants under six months and a susceptibility trough once it wanes. Direct support for antibody absence, rather than any intrinsic property of the toxin, being the permissive host state.

Superantigen Exotoxin Production

Toxigenic strains secrete superantigen exotoxins at the colonized or infected site. In staphylococcal disease the principal toxins are toxic shock syndrome toxin-1 (TSST-1) and the staphylococcal enterotoxins; in streptococcal disease they are the streptococcal pyrogenic exotoxins A, B and C together with streptococcal superantigen A.

biological process involved in interaction with host GO:0051701 ⚠ ABNORMAL

Downstream

Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking Secreted superantigen reaches host antigen-presenting cells and T cells at the site and systemically.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"The main described superantigenic exotoxins are toxic shock syndrome toxin-1 (TSST-1) and enterotoxins for Staphylococcus aureus and Streptococcal pyrogenic exotoxins (SpE) A, B, and C and streptococcal superantigen A (SsA) for Streptococcus pyogenes."

Enumerates the specific superantigen exotoxins produced by each causative organism, which is the content of this node.

Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking

The superantigen binds MHC class II on antigen-presenting cells outside the conventional peptide-binding groove and simultaneously engages the variable beta domain of the T cell receptor. This bridges the two cells without antigen processing or MHC restriction, so activation is determined by Vbeta usage rather than antigen specificity.

professional antigen presenting cell CL:0000145 T cell CL:0000084

MHC class II protein complex GO:0042613

Downstream

Massive Polyclonal T Cell Activation Cross-linking delivers an activating signal to every T cell carrying a responsive Vbeta element.

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"TSS results from the ability of bacterial toxins to act as superantigens, stimulating immune-cell expansion and rampant cytokine expression in a manner that bypasses normal MHC-restricted antigen processing."

States the defining superantigen property this node represents: activation that bypasses conventional MHC-restricted antigen processing.

Massive Polyclonal T Cell Activation

Because activation is Vbeta-restricted rather than antigen-specific, a very large fraction of the circulating T cell repertoire is activated simultaneously, orders of magnitude more than in a conventional antigen-driven response. Mutational analysis in rabbits establishes that this T cell activation step is required for the downstream toxicity, not merely a correlate of it.

T cell CL:0000084 macrophage CL:0000235

T cell activation GO:0042110 ↑ INCREASED

Animal models

Rabbit superantigen challenge model Rabbit perturbs Comparison of a TSST-1 mutant with reduced MHC binding against one with abolished T cell receptor binding isolates the T cell activation step and shows it is required for the toxic phenotype.

Downstream

Systemic Cytokine Storm Activated T cells and accessory monocytes/macrophages release proinflammatory cytokines.

Show evidence (2 references)

PMID:38247655 SUPPORT Human Clinical

"Bacterial superantigenic exotoxins induces unconventional polyclonal lymphocyte activation, which leads to rapid shock, multiple organ failure syndrome, and death."

Directly supports unconventional polyclonal lymphocyte activation as the step linking superantigen exposure to shock and organ failure.

PMID:22069685 SUPPORT Model Organism

"Here, we report that the mutant G31R induced all the biological effects of the wild type sAg, while the mutant with non-functional TCR binding did not retain any of the toxic effects, proving the pivotal role of T cells in this system."

Rabbit TSST-1 mutant analysis showing that abolishing T cell receptor binding abolishes toxicity, establishing T cell activation as required rather than incidental. Model organism evidence, complementing the human clinical support.

Systemic Cytokine Storm

Simultaneous activation of T cells and antigen-presenting cells produces an overwhelming, self-amplifying release of proinflammatory cytokines including TNF, IL-1beta, IL-2 and IFN-gamma. This mediator burst, rather than bacterial invasion itself, produces the systemic illness; in staphylococcal TSS the organism is frequently confined to a colonized mucosal or wound surface.

cytokine production GO:0001816 ↑ INCREASED tumor necrosis factor production GO:0032640 ↑ INCREASED interleukin-1 beta production GO:0032611 ↑ INCREASED inflammatory response GO:0006954 ↑ INCREASED

Downstream

Endothelial Injury and Capillary Leak Circulating cytokines act on vascular endothelium to increase permeability.

Distributive Shock and Multi-Organ Dysfunction Cytokine-driven tissue damage and coagulation activation contribute directly to organ dysfunction.

Show evidence (2 references)

PMID:19393958 SUPPORT Human Clinical

"A repetitive cycle of cell stimulation and cytokine release results in a cytokine avalanche that causes tissue damage, disseminated intravascular coagulation, and organ dysfunction."

Describes the self-amplifying cytokine cascade and links it to the tissue damage, coagulopathy and organ dysfunction this node feeds.

PMID:33477467 SUPPORT In Vitro

"rTSST-1 significantly induced interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) production in mouse macrophages and the production was dose-dependent"

Macrophage stimulation experiments showing TSST-1 dose-dependently induces IL-1beta and TNF-alpha, supporting the innate-cell contribution to the cytokine burst. Marked PARTIAL because this is a murine macrophage system addressing one cellular contributor rather than the systemic human cytokine storm.

Endothelial Injury and Capillary Leak

Cytokine-driven endothelial activation, compounded by direct superantigen action on endothelial cells, causes upregulation of adhesion molecules, loss of monolayer barrier function, plasma extravasation into the interstitium, hypoalbuminemia and loss of effective intravascular volume.

endothelial cell CL:0000115

regulation of vascular permeability GO:0043114 ↑ INCREASED

Downstream

Distributive Shock and Multi-Organ Dysfunction Capillary leak plus cytokine-mediated vasodilation produces refractory hypotension.

Show evidence (2 references)

PMID:38247655 SUPPORT Human Clinical

"This results in a massive release of proinflammatory cytokines, with clinical signs, such as capillary leakage, arterial hypotension, organ failure, and coagulation activation, usually being reported in this setting"

Links the cytokine release directly to capillary leakage and arterial hypotension, the content of this node and the next.

PMID:29229737 SUPPORT In Vitro

"TSST-1-mediated activation results in increased monolayer permeability and defects in vascular reendothelialization."

Human aortic endothelial cell experiments showing the superantigen itself increases endothelial permeability, supporting a direct endothelial contribution to capillary leak alongside the cytokine-mediated route.

Distributive Shock and Multi-Organ Dysfunction

Refractory hypotension with tissue hypoperfusion, together with direct cytokine-mediated injury and coagulation activation, produces the multisystem failure that defines the syndrome: acute kidney injury, hepatic dysfunction, thrombocytopenia and disseminated intravascular coagulation, rhabdomyolysis, acute respiratory distress, and encephalopathy.

inflammatory response GO:0006954 ↑ INCREASED

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"Toxic shock syndrome (TSS) is an acute, multi-system, toxin-mediated illness, often resulting in multi-organ failure."

Supports multi-organ failure as the terminal manifestation of the toxin-mediated cascade.

Bacterial Ribosomal Translation (Clindamycin/Linezolid Target)

Both causative organisms depend on 70S-ribosome translation. Clindamycin (a lincosamide) and linezolid (an oxazolidinone) bind the 50S subunit and arrest bacterial protein synthesis. In TSS this target is pursued not primarily for bacterial killing, which the beta-lactam provides, but because the superantigens are themselves translated products.

translation GO:0006412

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"Specific therapy focuses on early identification of the illness, source control, and administration on antimicrobial agents including drugs capable of suppressing toxin production (eg, clindamycin, linezolid)."

Identifies clindamycin and linezolid, both ribosome-targeting protein synthesis inhibitors, as the specific agents used in TSS therapy.

Suppression of Superantigen Synthesis by Protein-Synthesis Inhibitors

Because TSST-1 and the streptococcal pyrogenic exotoxins are secreted proteins, a ribosome-targeting antibiotic suppresses their production independently of bacterial killing. This anti-toxin rationale is why clindamycin is added to a bactericidal beta-lactam in TSS rather than used as a substitute for it, and it is the mechanistic basis for the observed mortality association with adjunctive clindamycin in streptococcal disease.

translation GO:0006412 ↓ DECREASED

Show evidence (2 references)

PMID:19393958 SUPPORT Human Clinical

"Specific therapy focuses on early identification of the illness, source control, and administration on antimicrobial agents including drugs capable of suppressing toxin production (eg, clindamycin, linezolid)."

Explicitly frames clindamycin and linezolid as agents capable of suppressing toxin production, which is the step this node represents.

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Separates eradication of toxin production and protein-synthesis-inhibiting therapy from bactericidal therapy, matching the distinction between this node and the peptidoglycan cross-linking node.

Ribosomal Target Resistance in Group A Streptococcus

The anti-toxin rationale for adjunctive clindamycin is contingent on the organism remaining susceptible to it. Ribosomal-target resistance, principally erm-mediated rRNA methylation, is rising sharply in invasive group A Streptococcus: isolates non-susceptible to macrolides and clindamycin went from 12.7% to 33.1% over a decade of US surveillance. This is a direct and growing threat to the toxin-suppression step above, and is why susceptibility testing now gates the adjunct.

response to antibiotic GO:0046677 ↑ INCREASED

Show evidence (1 reference)

PMID:40193120 SUPPORT Human Clinical

"Among tested isolates, those nonsusceptible to macrolides and clindamycin increased from 12.7% in 2013 to 33.1% in 2022."

Population-based surveillance quantifying the rise in clindamycin non-susceptibility among invasive group A streptococcal isolates, the resistance step this node represents.

Bacterial Peptidoglycan Cross-Linking (Beta-Lactam Target)

Both Staphylococcus aureus and Streptococcus pyogenes build the peptidoglycan cell wall by penicillin-binding protein transpeptidase cross-linking. Beta-lactam acylation of the PBP active site halts cross-linking and is bactericidal. This is the target of the antistaphylococcal penicillin or cefazolin used for methicillin-susceptible staphylococcal TSS and of the penicillin used for streptococcal TSS; methicillin-resistant strains express an altered PBP and require vancomycin or linezolid instead.

peptidoglycan-based cell wall biogenesis GO:0009273

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Establishes bactericidal antibiotic treatment as a distinct required component of TSS management; the beta-lactam PBP target is the step this node represents.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

16

Blood 2

Thrombocytopenia HP:0001873

Show evidence (2 references)

PMID:19393958 SUPPORT Human Clinical

"A repetitive cycle of cell stimulation and cytokine release results in a cytokine avalanche that causes tissue damage, disseminated intravascular coagulation, and organ dysfunction."

Supports cytokine-driven consumptive coagulopathy, of which thrombocytopenia is the corresponding count abnormality. Marked PARTIAL because the snippet names disseminated intravascular coagulation rather than the platelet count itself.

PMID:36456018 SUPPORT Human Clinical

"Clinical evidence of STSS included hypotension and at least two of the following: renal impairment, coagulopathy, liver function abnormality, acute respiratory distress syndrome, generalised erythematous macular rash (with desquamation), soft-tissue necrosis (including necrotising fasciitis,..."

Coagulopathy is a qualifying organ manifestation in the STSS criteria. Marked PARTIAL because the criteria name coagulopathy rather than the platelet threshold this phenotype records.

Disseminated Intravascular Coagulation HP:0005521

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"A repetitive cycle of cell stimulation and cytokine release results in a cytokine avalanche that causes tissue damage, disseminated intravascular coagulation, and organ dysfunction."

Directly names disseminated intravascular coagulation as a consequence of the cytokine cascade in TSS.

Cardiovascular 2

Hypotension HP:0002615

Temporal: ACUTE

Show evidence (2 references)

PMID:31151811 SUPPORT Human Clinical

"The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement)"

Hypotension is enumerated as a required CDC clinical criterion.

PMID:38247655 SUPPORT Human Clinical

"This results in a massive release of proinflammatory cytokines, with clinical signs, such as capillary leakage, arterial hypotension, organ failure, and coagulation activation, usually being reported in this setting"

Connects arterial hypotension mechanistically to the cytokine release cascade.

Conjunctival Hyperemia HP:0030953

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"The authors described a pediatric case series of seven children, with clinical presentations including high fever, cephalalgia, confusion, cutaneous rash, conjunctival hyperhemia, and digestive signs."

The index case series describing TSS names conjunctival hyperaemia directly among the presenting features. Quoted verbatim, including the source's spelling "hyperhemia".

Digestive 2

Vomiting HP:0002013

Temporal: ACUTE

Gastrointestinal toxicity in staphylococcal TSS traces to the staphylococcal enterotoxins rather than to TSST-1, which lacks the emetic cystine loop.

Show evidence (2 references)

PMID:38247655 SUPPORT Human Clinical

"Digestive signs (abdominal pain, diarrhea, and vomiting) and cephalalgia were very common"

A 102-case multicentre series of menstrual TSS naming vomiting directly and reporting it as very common.

PMID:40711134 SUPPORT Other

"This loop is responsible for the gastrointestinal toxicity observed with SEB, including its ability to induce vomiting, a feature not shared by TSST-1."

Attributes the emetic component of staphylococcal TSS to the enterotoxins' emetic cystine loop rather than to TSST-1, which lacks it. Evidence source is OTHER as this is a structural/mechanistic review.

Diarrhea HP:0002014

Temporal: ACUTE

Show evidence (2 references)

PMID:38247655 SUPPORT Human Clinical

"Digestive signs (abdominal pain, diarrhea, and vomiting) and cephalalgia were very common"

A 102-case multicentre series of menstrual TSS naming diarrhea directly and reporting it as very common.

PMID:32461307 SUPPORT Human Clinical

"In 1978, Todd et al. (4) identified an acute, severe illness characterized by high fever, generalized skin rash, conjunctival hyperemia, diarrhea, hypotension, and renal failure in seven children (8 to 17 years of age)."

The index description of TSS names diarrhea among the defining features.

Genitourinary 1

Acute Kidney Injury HP:0001919

Temporal: ACUTE

Show evidence (2 references)

PMID:36456018 SUPPORT Human Clinical

"Clinical evidence of STSS included hypotension and at least two of the following: renal impairment, coagulopathy, liver function abnormality, acute respiratory distress syndrome, generalised erythematous macular rash (with desquamation), soft-tissue necrosis (including necrotising fasciitis,..."

Renal impairment is named explicitly among the qualifying organ manifestations in the STSS case-ascertainment criteria.

PMID:32461307 SUPPORT Human Clinical

"In 1978, Todd et al. (4) identified an acute, severe illness characterized by high fever, generalized skin rash, conjunctival hyperemia, diarrhea, hypotension, and renal failure in seven children (8 to 17 years of age)."

The index description of TSS names renal failure among the defining features, supporting renal involvement in the staphylococcal form as well.

Immune 1

Diffuse Macular Erythroderma HP:0001019

Temporal: ACUTE

Show evidence (1 reference)

PMID:31151811 SUPPORT Human Clinical

"The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement)"

Rash is a required CDC clinical criterion. The preferred_term records the characteristic diffuse macular erythroderma, more specific than the bound HPO parent term.

Metabolism 1

Fever HP:0001945

Temporal: ACUTE

Show evidence (1 reference)

PMID:31151811 SUPPORT Human Clinical

"The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement)"

Fever is enumerated as one of the required CDC clinical criteria, supporting both its presence and its diagnostic role. No frequency band is asserted: because this is a required criterion, its rate among confirmed cases is an ascertainment artifact rather than a measured frequency.

Nervous System 1

Confusion HP:0001289

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"The authors described a pediatric case series of seven children, with clinical presentations including high fever, cephalalgia, confusion, cutaneous rash, conjunctival hyperhemia, and digestive signs."

The index TSS case series names confusion directly among the presenting features.

Respiratory 1

Acute Respiratory Distress Syndrome HP:0033677

Temporal: ACUTE

Show evidence (1 reference)

PMID:36456018 SUPPORT Human Clinical

"Clinical evidence of STSS included hypotension and at least two of the following: renal impairment, coagulopathy, liver function abnormality, acute respiratory distress syndrome, generalised erythematous macular rash (with desquamation), soft-tissue necrosis (including necrotising fasciitis,..."

Acute respiratory distress syndrome is named explicitly among the qualifying organ manifestations in the STSS case-ascertainment criteria.

Other 5

Palmoplantar Desquamation Palmoplantar scaling skin HP:0025524

Show evidence (2 references)

PMID:31151811 SUPPORT Human Clinical

"The diagnosis was confirmed by fulfilment of the clinical criteria outlined by the US Centers for Disease Control and Prevention (CDC; fever, rash, desquamation, hypotension, and multi-system involvement)"

Desquamation is enumerated as a required CDC clinical criterion. The bound HPO term describes palmoplantar scaling; preferred_term retains the clinical desquamation phrasing.

PMID:32461307 SUPPORT Human Clinical

"During convalescence, four girls and three boys had desquamation of the affected skin and peeling of the palms and soles of their feet."

The index case series describes palmoplantar desquamation directly, and places it in convalescence, matching the late timing recorded in this phenotype.

Strawberry Tongue HP:0031042

Show evidence (1 reference)

PMID:33304729 SUPPORT Human Clinical

"Strawberry tongue is a useful diagnostic feature in various diseases such as Kawasaki disease, TSS, scarlet fever, and group A streptococcal pharyngitis."

Names strawberry tongue as a diagnostic feature of TSS directly, replacing the earlier inference from its occurrence in scarlet fever.

Myositis HP:0100614

Show evidence (1 reference)

PMID:36456018 SUPPORT Human Clinical

"Clinical evidence of STSS included hypotension and at least two of the following: renal impairment, coagulopathy, liver function abnormality, acute respiratory distress syndrome, generalised erythematous macular rash (with desquamation), soft-tissue necrosis (including necrotising fasciitis,..."

The STSS case-ascertainment criteria used by this systematic review name myositis explicitly among the qualifying organ manifestations.

Elevated Transaminases Elevated circulating aspartate aminotransferase concentration HP:0031956

Show evidence (1 reference)

PMID:36456018 SUPPORT Human Clinical

"Clinical evidence of STSS included hypotension and at least two of the following: renal impairment, coagulopathy, liver function abnormality, acute respiratory distress syndrome, generalised erythematous macular rash (with desquamation), soft-tissue necrosis (including necrotising fasciitis,..."

Liver function abnormality is named explicitly among the qualifying organ manifestations in the STSS case-ascertainment criteria.

Necrotizing Soft Tissue Infection Fasciitis HP:0100537

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Streptococcal TSS is linked to a severe group A streptococcal infection and, most frequently, to a necrotizing soft tissue infection."

Directly associates necrotizing soft tissue infection with streptococcal TSS. HPO has no necrotizing-fasciitis term, so the parent Fasciitis is bound and the specific clinical entity is carried in preferred_term.

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Genetic Associations

2

HLA-DRB1 (HLA class II genotype is the best-characterized human genetic modifier of TSS susceptibility. It does not cause disease directly; it sets the magnitude of the anti-TSST-1 antibody response, and therefore whether a host can neutralize the superantigen on exposure. HLA-DRB1*03:01 is positively associated with anti-TSST-1 antibody levels, whereas HLA-DRB1*01:01 is negatively associated.)

Gene: HLA-DRB1 hgnc:4948 relationship_type: SUSCEPTIBILITY

Show evidence (1 reference)

PMID:37731490 SUPPORT Human Clinical

"Moreover, the anti-TSST-1 antibody levels were strongly associated with HLA class II gene loci."

Genome-wide association analysis in 976 population-based participants showing HLA class II loci govern the anti-TSST-1 antibody response that determines susceptibility.

HLA-DQB1 (HLA-DQB1*02:01 is positively and HLA-DQB1*05:01 negatively associated with anti-TSST-1 antibody levels, acting with HLA-DRB1 as a susceptibility modifier through the humoral antitoxin response rather than through any direct disease mechanism.)

Gene: HLA-DQB1 hgnc:4944 relationship_type: SUSCEPTIBILITY

Show evidence (1 reference)

PMID:37731490 SUPPORT Human Clinical

"Moreover, the anti-TSST-1 antibody levels were strongly associated with HLA class II gene loci."

Same population-based genetic analysis identifying HLA class II loci, including HLA-DQB1, as determinants of the protective antibody response.

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Medical Actions

6

Source control

Action: surgical procedure Ontology label: Surgical Procedure NCIT:C15329

Immediate removal of the inciting focus: withdrawal of a retained tampon, nasal packing or other foreign body, and emergent surgical debridement of infected or necrotic soft tissue in streptococcal disease. Source control removes the site of ongoing toxin elaboration and is repeatedly identified as one of the principal modifiable determinants of survival.

Mechanism Target:

Superantigen Exotoxin Production — Removing the colonized device or debriding necrotic tissue eliminates the niche in which superantigen is being produced.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"source control and eradication of toxin production"

Pairs source control directly with eradication of toxin production, the mechanism node this treatment targets.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Lists source control and eradication of toxin production as core components of emergency TSS management.

Bactericidal beta-lactam antibiotic therapy

Action: antibiotic therapy Ontology label: Antibiotic Therapy NCIT:C15620

Agent: penicillin CHEBI:17334 vancomycin CHEBI:28001

A bactericidal agent directed at the causative organism: penicillin for group A Streptococcus, and an antistaphylococcal penicillin or cefazolin for methicillin-susceptible Staphylococcus aureus. Vancomycin or linezolid replaces the beta-lactam when methicillin resistance is present or suspected empirically.

Mechanism Target:

Bacterial Peptidoglycan Cross-Linking (Beta-Lactam Target) — Beta-lactams acylate the penicillin-binding protein transpeptidase and halt peptidoglycan cross-linking, killing the organism.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Establishes bactericidal antibiotic therapy as a component of TSS management. Marked PARTIAL because the review states the clinical role rather than the penicillin-binding-protein mechanism, which is carried on the target node.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Establishes bactericidal antibiotic therapy as a required, distinct component of TSS management.

Adjunctive protein-synthesis-inhibiting antibiotic therapy

Action: antibiotic therapy Ontology label: Antibiotic Therapy NCIT:C15620

Agent: clindamycin CHEBI:3745 linezolid CHEBI:63607

Clindamycin, or linezolid where clindamycin cannot be used, is added to the bactericidal agent specifically to suppress superantigen synthesis. In invasive beta-haemolytic streptococcal infection adjunctive clindamycin added to a beta-lactam is associated with lower mortality, and in streptococcal TSS specifically a meta-analysis found a significant association between clindamycin treatment and reduced mortality, although the certainty of that evidence was rated low.

Mechanism Target:

Bacterial Ribosomal Translation (Clindamycin/Linezolid Target) — Clindamycin and linezolid bind the 50S ribosomal subunit and arrest bacterial protein synthesis.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"protein synthesis inhibiting antibiotic administration"

Names protein-synthesis inhibition as the therapeutic action, which is the bacterial translation target this link points to.

Suppression of Superantigen Synthesis by Protein-Synthesis Inhibitors — Arresting translation suppresses production of the secreted superantigen driving the syndrome, independently of bacterial killing.

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"drugs capable of suppressing toxin production (eg, clindamycin, linezolid)"

Names clindamycin and linezolid specifically as toxin-production-suppressing drugs, which is the mechanism node this link targets.

Show evidence (3 references)

PMID:19393958 SUPPORT Human Clinical

"Specific therapy focuses on early identification of the illness, source control, and administration on antimicrobial agents including drugs capable of suppressing toxin production (eg, clindamycin, linezolid)."

Names clindamycin and linezolid as the toxin-suppressing agents used in TSS.

PMID:36456018 SUPPORT Human Clinical

"We found a statistically significant association between clindamycin treatment and mortality"

Meta-analysis reporting a significant clindamycin-mortality association in streptococcal TSS; the authors' own low-certainty caveat is preserved in the treatment description.

PMID:33333013 SUPPORT Human Clinical

"Clindamycin is strongly recommended as an adjunctive treatment to β-lactam antibiotics in patients with severe invasive group A β-haemolytic streptococcal (iGAS) infections."

States the guideline position on adjunctive clindamycin in invasive group A streptococcal infection. Marked PARTIAL because the cohort addresses invasive streptococcal infection broadly rather than toxic shock syndrome specifically.

Intravenous immunoglobulin

Action: intravenous immunoglobulin therapy Ontology label: Intravenous Immunoglobulin Therapy NCIT:C121331

High-dose polyspecific intravenous immunoglobulin is used as an adjunct on the rationale that pooled donor immunoglobulin contains neutralizing antibody against the superantigen, supplying the antitoxin the host lacks. The evidence is genuinely contested: a meta-analysis restricted to clindamycin-treated streptococcal TSS found mortality fell from 33.7% to 15.7%, whereas a Japanese nationwide observational study of invasive group A streptococcal infection found no adjusted survival benefit. See the recorded discussion on this conflict.

Mechanism Target:

Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking — Pooled immunoglobulin is proposed to neutralize circulating superantigen before it can bridge MHC class II and the T cell receptor.

Show evidence (1 reference)

PMID:19393958 SUPPORT Human Clinical

"Intravenous immunoglobulin has the potential to neutralise superantigen and to mitigate subsequent tissue damage."

States the superantigen-neutralization mechanism, which is the cross-linking node this link targets.

Show evidence (3 references)

PMID:29788397 SUPPORT Human Clinical

"In association with IVIG, mortality fell from 33.7% to 15.7% with remarkable consistency across the single randomized and four nonrandomized studies."

Meta-analysis in clindamycin-treated streptococcal TSS reporting a mortality reduction associated with IVIG.

PMID:37586661 REFUTE Human Clinical

"IVIG administration had no survival benefit in iGAS patients."

Nationwide observational cohort of 481 patients finding no adjusted mortality benefit of IVIG, directly opposing the meta-analytic estimate. Retained as REFUTE so the conflict is visible rather than resolved by curator preference.

PMID:19393958 SUPPORT Human Clinical

"Intravenous immunoglobulin has the potential to neutralise superantigen and to mitigate subsequent tissue damage."

States the superantigen-neutralization rationale that motivates the target_mechanisms link.

Fluid resuscitation and vasopressor support

Action: supportive care Ontology label: Supportive Care NCIT:C15747

Aggressive intravenous crystalloid resuscitation to replace the volume lost to capillary leak, followed by vasopressors for fluid-refractory shock, together with intensive-care organ support.

Mechanism Target:

Distributive Shock and Multi-Organ Dysfunction — Volume replacement and vasopressors counter the distributive shock produced by capillary leak and vasodilation, without addressing the toxin itself.

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Establishes immediate resuscitation as a required management step. Marked PARTIAL because it is supportive rather than mechanism-directed therapy, so the link is to the shock node it counteracts rather than to a drug target.

Target Phenotypes: Hypotension HP:0002615

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Management of TSS is a medical emergency and relies on early detection, immediate resuscitation, source control and eradication of toxin production, bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic administration."

Lists immediate resuscitation as a core component of emergency TSS management.

Recombinant detoxified TSST-1 variant vaccine

Action: vaccination Ontology label: Vaccination NCIT:C15346

An investigational active-immunoprophylaxis approach targeting the core superantigen mechanism directly. A recombinant detoxified TSST-1 variant (rTSST-1v) was safe and immunogenic in a first-in-human dose-escalation trial. It is not licensed, and no efficacy against clinical TSS has been demonstrated.

Mechanism Target:

Absent or Low Neutralizing Antitoxin Antibody — Active immunization is intended to induce the neutralizing antitoxin antibody whose absence is the principal host susceptibility factor.

Show evidence (1 reference)

PMID:27296693 SUPPORT Human Clinical

"We aimed to assess the safety, tolerability, and immunogenicity of a recombinant detoxified toxic shock syndrome toxin-1 variant (rTSST-1v) vaccine in adult volunteers."

The trial's immunogenicity endpoint is the antitoxin antibody response this link targets. Marked PARTIAL because immunogenicity in volunteers is not demonstrated protection against clinical TSS.

Show evidence (2 references)

PMID:27296693 SUPPORT Human Clinical

"We aimed to assess the safety, tolerability, and immunogenicity of a recombinant detoxified toxic shock syndrome toxin-1 variant (rTSST-1v) vaccine in adult volunteers."

Establishes the existence and objective of the first-in-human rTSST-1v vaccine trial.

PMID:27296693 SUPPORT Human Clinical

"Staphylococcal toxic shock syndrome is a superantigen-driven potentially life-threatening disease affecting mainly young and otherwise healthy individuals. Currently, no specific treatment or preventive measure is available."

Supports the recorded caveat that no licensed specific preventive measure exists, which is why this entry is curated as investigational.

🔬

Diagnosis

1

Culture of the suspected focus and sterile sites

Blood, wound, and mucosal-site cultures are obtained. In streptococcal TSS Streptococcus pyogenes is frequently recovered from a normally sterile site, which is required for a confirmed case; in staphylococcal TSS blood cultures are often negative because the organism remains at a colonized surface while the toxin acts systemically.

diagnostic procedure NCIT:C18020

Results: Isolation of a superantigen-producing Staphylococcus aureus or Streptococcus pyogenes strain in a compatible clinical syndrome.

Show evidence (1 reference)

PMID:31151811 SUPPORT Human Clinical

"as well as a nasal swab positive for the S aureus strain and presence of the gene encoding for toxic shock syndrome toxin 1 (TSST-1)."

Illustrates microbiological confirmation by recovery of the organism together with demonstration of the toxin gene.

📊

Prevalence

3

Worldwide, menstruating individuals

Annual Incidence 0.265 per 100,000 (0.03–0.5) <1 in 1,000,000 Staphylococcal TSS

Menstrual toxic shock syndrome incidence reported as 0.03-0.50 per 100,000 people; rate_per_100000 records the midpoint of that range.

Show evidence (1 reference)

PMID:31151811 SUPPORT Human Clinical

"Incidence ranges from 0·03 to 0·50 cases per 100 000 people, with overall mortality around 8%."

Systematic review quantifying menstrual TSS incidence and mortality.

US children aged 1-18 hospitalized with septic shock

Cases In Literature Unknown

Proportion of pediatric septic shock attributable to TSS (909 of 8,226 cases, 11.1%) in a multicenter US administrative-database analysis; a case fraction within a hospitalized population, not a population rate.

Show evidence (1 reference)

PMID:29601458 SUPPORT Human Clinical

"Of 8,226 cases of pediatric septic shock, 909 (11.1%) were classified as TSS and 562 (6.8%) were possible TSS cases."

Quantifies the contribution of TSS to the burden of pediatric septic shock in the United States.

10 US states, invasive group A streptococcal disease (2013-2022)

Annual Incidence Unknown Streptococcal TSS

Denominator context only, deliberately carrying no numeric rate. Population-based Active Bacterial Core surveillance recorded INVASIVE group A streptococcal disease rising from 3.6 to 8.2 per 100,000 between 2013 and 2022. Streptococcal TSS is a subset of that population, so those figures are not an STSS incidence and are left out of `rate_per_100000` rather than being placed in a field a consumer would read as the subtype's rate. They are also trend endpoints for two different years, not an uncertainty interval, so they would misuse `rate_low`/`rate_high` as well. The quoted figures remain in the evidence snippet, where their meaning is explicit.

Show evidence (1 reference)

PMID:40193120 SUPPORT Human Clinical

"Incidence rose from 3.6 per 100 000 persons in 2013 to 8.2 per 100 000 persons in 2022 (P < .001 for trend)."

Quantifies the rising incidence of invasive GAS disease. Marked PARTIAL because the measure is invasive GAS disease overall rather than streptococcal TSS specifically.

🦠

Infectious Agent

2

Staphylococcus aureus

Superantigen-producing Staphylococcus aureus strains cause staphylococcal toxic shock syndrome. The organism frequently colonizes rather than overtly infects the portal of entry, and blood cultures are often negative.

Staphylococcus aureus NCBITaxon:1280

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Toxic shock syndrome (TSS) is a rare, life-threatening, toxin-mediated infectious process linked, in the vast majority of cases, to toxin-producing strains of Staphylococcus aureus or Streptococcus pyogenes."

Identifies toxin-producing Staphylococcus aureus as one of the two causative organisms of toxic shock syndrome.

Streptococcus pyogenes

Group A Streptococcus causes streptococcal toxic shock syndrome, typically in the setting of documented invasive infection such as necrotizing fasciitis, where the organism is frequently recovered from a normally sterile site.

Streptococcus pyogenes NCBITaxon:1314

Show evidence (1 reference)

PMID:38247655 SUPPORT Human Clinical

"Streptococcal TSS is linked to a severe group A streptococcal infection and, most frequently, to a necrotizing soft tissue infection."

Identifies Streptococcus pyogenes as the causative organism of the streptococcal form, arising from invasive infection.

📊

Related Datasets

4

Delineating the molecular pathways regulated by IFN-gamma and IL-17 in the small intestines of humanized mice during staphylococcal superantigen-induced toxic shock syndrome geo:GSE130125

RNASeq identified several pathways that were differentially expressed/regulated in the small intestines that correlated with intestinal failure during toxic shock syndrome caused by staphylococcal superantigen in a humanized mouse model

mouse BULK RNA SEQ n=21

PMID:32676080

Identified by GEO DataSets index search for Toxic Shock Syndrome (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-11. Title, sample count, and organism are GEO's own values. Relevance triaged manually: the study is explicitly a staphylococcal superantigen-induced TSS model in HLA-humanized mice.

Late Multiple Organ Surge in Interferon-regulated Target Genes Characterizes Staphylococcal Enterotoxin B Lethality geo:GSE52474

Bacterial superantigens are virulence factors that cause toxic shock syndrome. Here, the genome-wide, temporal response of mice to lethal intranasal staphylococcal enterotoxin B (SEB) was investigated in six tissues (PBMC, lung, spleen, kidney, heart, Liver).

mouse MICROARRAY n=154

PMID:24551153

Identified by GEO DataSets index search for Toxic Shock Syndrome (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-11. Relevance triaged manually: a multi-tissue time course of lethal superantigen challenge, matching the multi-organ dysfunction node.

Comparison of Transcriptional Signatures of Three Staphylococcal Superantigenic Toxins in Human Epidermal Melanocytes geo:GSE124756

The focus of this study was to determine the distinct and shared mechanisms of response to three toxins of the superantigenic family, namely SEA, SEB and TSST-1.

human MICROARRAY n=19

PMID:35740423

Identified by GEO DataSets index search for Toxic Shock Syndrome (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-11. Relevance triaged manually: a human-cell comparison of the three staphylococcal superantigens named in this entry's toxin-production node.

Gene Expression Changes Induced by Bacterial Superantigen, Staphylococcal Enterotoxin B geo:GSE15571

Toxic shock syndrome (TSS) is an acute, serious systemic illness caused by bacterial superantigens (BSAg). We characterized the early molecular events underlying TSS using our HLA-DR3 transgenic mouse model and studied gene expression profiling using DNA microarrays.

mouse MICROARRAY n=16

PMID:19336531

Identified by GEO DataSets index search for Toxic Shock Syndrome (scripts/discover_datasets.py); accession and metadata verified against NCBI E-utilities on 2026-08-11. Relevance triaged manually: an HLA-DR3 transgenic mouse TSS model, the humanized-MHC approach that overcomes wild-type murine superantigen resistance.

🔬

Clinical Trials

1

NCT02340338 PHASE_I COMPLETED

First-in-human, randomised, double-blind, adjuvant-controlled dose-escalation trial of the recombinant detoxified TSST-1 variant vaccine in 46 healthy adults, assessing safety, tolerability and anti-TSST-1 antibody response. Reported in PMID:27296693.

Target Phenotypes: Hypotension HP:0002615

Show evidence (2 references)

clinicaltrials:NCT02340338 SUPPORT Human Clinical

"The aim of this study is to demonstrate the safety and tolerability of the BioMed recombinant toxic shock syndrome toxin (rTSST-1) Variant Vaccine in healthy adults."

Trial registry record for the rTSST-1v vaccine curated in the treatments section, confirming its phase, design and objective.

clinicaltrials:NCT02340338 SUPPORT Human Clinical

"Toxic shock syndrome toxin (TSST-1) being responsible for almost all of menstruation associated and more than 50% of all other cases."

Quantifies why TSST-1 is the vaccine target: it accounts for nearly all menstrual and over half of non-menstrual staphylococcal TSS.

🐁

Animal Models

1

Rabbit superantigen challenge model

The rabbit is the standard experimental model for TSS because its sensitivity to staphylococcal and streptococcal superantigens is comparable to that of humans, unlike wild-type mice whose MHC class II binds these toxins poorly. Challenge with TSST-1 and structure-guided mutants was used to dissect which binding interface drives toxicity.

Species

Rabbit

Genotype

Wild type

Publication

PMID:22069685

Pathograph links

Massive Polyclonal T Cell Activation perturbs fidelity: moderate Comparison of a TSST-1 mutant with reduced MHC binding against one with abolished T cell receptor binding isolates the T cell activation step and shows it is required for the toxic phenotype.

Limitations: The model delivers purified toxin by direct challenge rather than reproducing toxin elaboration by a colonizing organism, and does not capture the human menstrual or wound microenvironment in which superantigen is naturally produced. Co-treatment with lipopolysaccharide is used to elicit the full inflammatory response.

Readouts

Lymphocyte proliferation and IL-2 gene expression after in vivo toxin challenge

Direction: INCREASED

Interpretation: Read as the T cell activation output of superantigen challenge; abolished when the T cell receptor binding site is mutated.

Show evidence (1 reference)

PMID:22069685 SUPPORT Model Organism

"T cell activation has been assessed by lymphocyte proliferation and IL-2 gene expression after in vivo challenge with TSST-1 and the mutant antigens"

States the specific readouts used to measure T cell activation in this model.

Show evidence (1 reference)

PMID:22069685 SUPPORT Model Organism

"Our experimental model of choice is the rabbit because it is comparable to humans in its sensitivity to sAg."

Justifies the rabbit as informative for human superantigen biology on the basis of comparable superantigen sensitivity.

Show evidence (1 reference)

PMID:22069685 SUPPORT Model Organism

"Staphylococcal superantigens (sAgs), such as toxic shock syndrome toxin 1 (TSST-1), induce massive cytokine production, which may result in toxic shock syndrome (TSS) and sepsis."

Establishes that the superantigen challenge this model administers reproduces the massive cytokine production underlying toxic shock syndrome, which is what makes the model informative for the disease.

{ }

Source YAML

click to show

name: Toxic Shock Syndrome
creation_date: '2026-08-11T00:00:00Z'
description: >-
  Toxic shock syndrome (TSS) is an acute, life-threatening, toxin-mediated multisystem
  illness caused by superantigen-producing strains of Staphylococcus aureus or
  Streptococcus pyogenes. Superantigen exotoxins bind major histocompatibility complex
  class II molecules outside the conventional peptide-binding groove and simultaneously
  engage the variable beta chain of the T cell receptor, bypassing antigen processing
  and driving polyclonal activation of a large fraction of the T cell repertoire. The
  resulting cytokine storm produces capillary leak, refractory hypotension, and
  multi-organ dysfunction, with the characteristic diffuse erythroderma and late
  palmoplantar desquamation.
category: Infectious Disease
disease_term:
  preferred_term: toxic shock syndrome
  term:
    id: MONDO:0001881
    label: toxic shock syndrome
parents:
- Bacterial infection
references:
- reference: PMID:38247655
  title: "Toxic Shock Syndrome: A Literature Review."
- reference: PMID:19393958
  title: "Gram-positive toxic shock syndromes."
has_subtypes:
- name: Staphylococcal TSS
  display_name: Staphylococcal toxic shock syndrome
  description: >-
    Toxic shock syndrome caused by Staphylococcus aureus superantigens, classically
    toxic shock syndrome toxin-1 (TSST-1) and the staphylococcal enterotoxins. It is
    subdivided clinically into menstrual TSS, historically linked to high-absorbency
    tampon use, and non-menstrual TSS arising from surgical wounds, burns, nasal
    packing, or postpartum infection. Case fatality is substantially lower than in the
    streptococcal form.
  subtype_term:
    preferred_term: staphylococcal toxic-shock syndrome
    term:
      id: MONDO:0020545
      label: staphylococcal toxic-shock syndrome
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Staphylococcal TSS can be menstrual or nonmenstrual.
    explanation: >-
      Supports the staphylococcal subtype and its menstrual/non-menstrual clinical
      division.
- name: Streptococcal TSS
  display_name: Streptococcal toxic shock syndrome
  description: >-
    Toxic shock syndrome caused by Streptococcus pyogenes superantigens, principally
    the streptococcal pyrogenic exotoxins and streptococcal superantigen A. It arises
    in the setting of a severe invasive group A streptococcal infection, most often a
    necrotizing soft tissue infection, and carries markedly higher mortality than
    staphylococcal TSS.
  subtype_term:
    preferred_term: streptococcal toxic-shock syndrome
    term:
      id: MONDO:0020544
      label: streptococcal toxic-shock syndrome
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Streptococcal TSS is linked to a severe group A streptococcal infection and,
      most frequently, to a necrotizing soft tissue infection.
    explanation: >-
      Supports the streptococcal subtype definition and its characteristic association
      with invasive necrotizing soft tissue infection.
infectious_agent:
- name: Staphylococcus aureus
  infectious_agent_term:
    preferred_term: Staphylococcus aureus
    term:
      id: NCBITaxon:1280
      label: Staphylococcus aureus
  description: >-
    Superantigen-producing Staphylococcus aureus strains cause staphylococcal toxic
    shock syndrome. The organism frequently colonizes rather than overtly infects the
    portal of entry, and blood cultures are often negative.
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Toxic shock syndrome (TSS) is a rare, life-threatening, toxin-mediated
      infectious process linked, in the vast majority of cases, to toxin-producing
      strains of Staphylococcus aureus or Streptococcus pyogenes.
    explanation: >-
      Identifies toxin-producing Staphylococcus aureus as one of the two causative
      organisms of toxic shock syndrome.
- name: Streptococcus pyogenes
  infectious_agent_term:
    preferred_term: Streptococcus pyogenes
    term:
      id: NCBITaxon:1314
      label: Streptococcus pyogenes
  description: >-
    Group A Streptococcus causes streptococcal toxic shock syndrome, typically in the
    setting of documented invasive infection such as necrotizing fasciitis, where the
    organism is frequently recovered from a normally sterile site.
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Streptococcal TSS is linked to a severe group A streptococcal infection and,
      most frequently, to a necrotizing soft tissue infection.
    explanation: >-
      Identifies Streptococcus pyogenes as the causative organism of the streptococcal
      form, arising from invasive infection.
prevalence:
- subtype: Staphylococcal TSS
  population: Worldwide, menstruating individuals
  measure_type: ANNUAL_INCIDENCE
  prevalence_class: BELOW_1_IN_1000000
  rate_per_100000: 0.265
  rate_low: 0.03
  rate_high: 0.5
  notes: >-
    Menstrual toxic shock syndrome incidence reported as 0.03-0.50 per 100,000 people;
    rate_per_100000 records the midpoint of that range.
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Incidence ranges from 0·03 to 0·50 cases per 100 000 people, with overall
      mortality around 8%.
    explanation: >-
      Systematic review quantifying menstrual TSS incidence and mortality.
- population: US children aged 1-18 hospitalized with septic shock
  measure_type: CASES_IN_LITERATURE
  prevalence_class: UNKNOWN
  notes: >-
    Proportion of pediatric septic shock attributable to TSS (909 of 8,226 cases,
    11.1%) in a multicenter US administrative-database analysis; a case fraction
    within a hospitalized population, not a population rate.
  evidence:
  - reference: PMID:29601458
    reference_title: "Epidemiology and Clinical Relevance of Toxic Shock Syndrome in US Children."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Of 8,226 cases of pediatric septic shock, 909 (11.1%) were classified as TSS and
      562 (6.8%) were possible TSS cases.
    explanation: >-
      Quantifies the contribution of TSS to the burden of pediatric septic shock in the
      United States.
- subtype: Streptococcal TSS
  population: 10 US states, invasive group A streptococcal disease (2013-2022)
  measure_type: ANNUAL_INCIDENCE
  prevalence_class: UNKNOWN
  notes: >-
    Denominator context only, deliberately carrying no numeric rate. Population-based
    Active Bacterial Core surveillance recorded INVASIVE group A streptococcal disease
    rising from 3.6 to 8.2 per 100,000 between 2013 and 2022. Streptococcal TSS is a
    subset of that population, so those figures are not an STSS incidence and are left
    out of `rate_per_100000` rather than being placed in a field a consumer would read
    as the subtype's rate. They are also trend endpoints for two different years, not
    an uncertainty interval, so they would misuse `rate_low`/`rate_high` as well. The
    quoted figures remain in the evidence snippet, where their meaning is explicit.
  evidence:
  - reference: PMID:40193120
    reference_title: "Invasive Group A Streptococcal Infections in 10 US States."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Incidence rose from 3.6 per 100 000 persons in 2013 to 8.2 per 100 000 persons in
      2022 (P < .001 for trend).
    explanation: >-
      Quantifies the rising incidence of invasive GAS disease. Marked PARTIAL because
      the measure is invasive GAS disease overall rather than streptococcal TSS
      specifically.
classifications:
  harrisons_chapter:
  - classification_value: INFECTIOUS_DISEASES
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Toxic shock syndrome (TSS) is a rare, life-threatening, toxin-mediated
        infectious process linked, in the vast majority of cases, to toxin-producing
        strains of Staphylococcus aureus or Streptococcus pyogenes.
      explanation: >-
        TSS is a bacterial toxin-mediated infectious process, placing it in Harrison's
        Infectious Diseases Part.
pathophysiology:
- name: Absent or Low Neutralizing Antitoxin Antibody
  description: >-
    Most adults acquire neutralizing antibody to TSST-1 through subclinical
    colonization. Individuals who lack such antibody at the time of toxin exposure are
    unable to neutralize the superantigen, and this deficit is the principal recognized
    host susceptibility determinant for staphylococcal TSS. Antibody levels are
    strongly determined by both the degree of colonization-driven toxin exposure and
    HLA class II genotype.
  biological_scale: ORGANISM
  role: susceptibility_factor
  downstream:
  - target: Superantigen Exotoxin Production
    description: >-
      Without neutralizing antitoxin, secreted superantigen reaches its host receptors
      and initiates the disease cascade.
    evidence:
    - reference: PMID:6491377
      reference_title: "Antibody responses to toxic-shock-syndrome (TSS) toxin by patients with TSS and by healthy staphylococcal carriers."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        The data suggest that absence of antibodies to the TSS toxin may be a
        predisposing factor in the development of clinical disease.
      explanation: >-
        Supports the predisposing direction of this edge: lacking antitoxin is what
        permits secreted superantigen to produce clinical disease.
  biological_processes:
  - preferred_term: humoral immune response
    modifier: DECREASED
    term:
      id: GO:0006959
      label: humoral immune response
  evidence:
  - reference: PMID:6491377
    reference_title: "Antibody responses to toxic-shock-syndrome (TSS) toxin by patients with TSS and by healthy staphylococcal carriers."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The data suggest that absence of antibodies to the TSS toxin may be a
      predisposing factor in the development of clinical disease.
    explanation: >-
      Case-control serology showing antitoxin levels are significantly lower in women
      with TSS than in controls, supporting absent antibody as a predisposing host
      factor.
  - reference: PMID:37731490
    reference_title: "Toxin exposure and HLA alleles determine serum antibody binding to toxic shock syndrome toxin 1 (TSST-1) of Staphylococcus aureus."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A well-known risk factor is the lack of neutralizing antibodies.
    explanation: >-
      Population-based study confirming lack of neutralizing antibody as the recognized
      risk factor this node represents.
  - reference: PMID:20036064
    reference_title: "Toxic shock syndrome toxin-1 (TSST-1) antibody levels in Japanese children."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Children are at risk of developing staphylococcal toxic shock syndrome when their
      immune system is immature and they have no protective circulating anti-TSS
      antibodies.
    explanation: >-
      Age-stratified serology showing risk tracks the absence of circulating antitoxin,
      with maternally derived antibody protecting infants under six months and a
      susceptibility trough once it wanes. Direct support for antibody absence, rather
      than any intrinsic property of the toxin, being the permissive host state.
- name: Superantigen Exotoxin Production
  description: >-
    Toxigenic strains secrete superantigen exotoxins at the colonized or infected site.
    In staphylococcal disease the principal toxins are toxic shock syndrome toxin-1
    (TSST-1) and the staphylococcal enterotoxins; in streptococcal disease they are the
    streptococcal pyrogenic exotoxins A, B and C together with streptococcal
    superantigen A.
  biological_scale: MOLECULAR
  downstream:
  - target: Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking
    description: >-
      Secreted superantigen reaches host antigen-presenting cells and T cells at the
      site and systemically.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Superantigenic exotoxins are able to induce unconventional activation of T
        cells by antigen-presenting cells (APCs).
      explanation: >-
        States that the secreted exotoxins act by engaging antigen-presenting cells and
        T cells, which is the transition this edge encodes.
  biological_processes:
  - preferred_term: biological process involved in interaction with host
    modifier: ABNORMAL
    term:
      id: GO:0051701
      label: biological process involved in interaction with host
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The main described superantigenic exotoxins are toxic shock syndrome toxin-1
      (TSST-1) and enterotoxins for Staphylococcus aureus and Streptococcal pyrogenic
      exotoxins (SpE) A, B, and C and streptococcal superantigen A (SsA) for
      Streptococcus pyogenes.
    explanation: >-
      Enumerates the specific superantigen exotoxins produced by each causative
      organism, which is the content of this node.
- name: Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking
  description: >-
    The superantigen binds MHC class II on antigen-presenting cells outside the
    conventional peptide-binding groove and simultaneously engages the variable beta
    domain of the T cell receptor. This bridges the two cells without antigen
    processing or MHC restriction, so activation is determined by Vbeta usage rather
    than antigen specificity.
  biological_scale: MOLECULAR
  downstream:
  - target: Massive Polyclonal T Cell Activation
    description: >-
      Cross-linking delivers an activating signal to every T cell carrying a responsive
      Vbeta element.
    evidence:
    - reference: PMID:19393958
      reference_title: "Gram-positive toxic shock syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        TSS results from the ability of bacterial toxins to act as superantigens,
        stimulating immune-cell expansion and rampant cytokine expression in a manner
        that bypasses normal MHC-restricted antigen processing.
      explanation: >-
        Links the non-MHC-restricted binding mode directly to immune-cell expansion,
        which is the step this edge encodes.
  cell_types:
  - preferred_term: professional antigen presenting cell
    term:
      id: CL:0000145
      label: professional antigen presenting cell
  - preferred_term: T cell
    term:
      id: CL:0000084
      label: T cell
  cellular_components:
  - preferred_term: MHC class II protein complex
    term:
      id: GO:0042613
      label: MHC class II protein complex
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      TSS results from the ability of bacterial toxins to act as superantigens,
      stimulating immune-cell expansion and rampant cytokine expression in a manner
      that bypasses normal MHC-restricted antigen processing.
    explanation: >-
      States the defining superantigen property this node represents: activation that
      bypasses conventional MHC-restricted antigen processing.
- name: Massive Polyclonal T Cell Activation
  description: >-
    Because activation is Vbeta-restricted rather than antigen-specific, a very large
    fraction of the circulating T cell repertoire is activated simultaneously, orders
    of magnitude more than in a conventional antigen-driven response. Mutational
    analysis in rabbits establishes that this T cell activation step is required for
    the downstream toxicity, not merely a correlate of it.
  biological_scale: CELLULAR
  downstream:
  - target: Systemic Cytokine Storm
    description: >-
      Activated T cells and accessory monocytes/macrophages release proinflammatory
      cytokines.
    evidence:
    - reference: PMID:19393958
      reference_title: "Gram-positive toxic shock syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        A repetitive cycle of cell stimulation and cytokine release results in a
        cytokine avalanche that causes tissue damage, disseminated intravascular
        coagulation, and organ dysfunction.
      explanation: >-
        Describes activated-cell stimulation feeding forward into the cytokine
        avalanche, which is the transition this edge encodes.
  cell_types:
  - preferred_term: T cell
    term:
      id: CL:0000084
      label: T cell
  - preferred_term: macrophage
    term:
      id: CL:0000235
      label: macrophage
  biological_processes:
  - preferred_term: T cell activation
    modifier: INCREASED
    term:
      id: GO:0042110
      label: T cell activation
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Bacterial superantigenic exotoxins induces unconventional polyclonal lymphocyte
      activation, which leads to rapid shock, multiple organ failure syndrome, and
      death.
    explanation: >-
      Directly supports unconventional polyclonal lymphocyte activation as the step
      linking superantigen exposure to shock and organ failure.
  - reference: PMID:22069685
    reference_title: "Staphylococcal superantigen (TSST-1) mutant analysis reveals that t cell activation is required for biological effects in the rabbit including the cytokine storm."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Here, we report that the mutant G31R induced all the biological effects of the
      wild type sAg, while the mutant with non-functional TCR binding did not retain
      any of the toxic effects, proving the pivotal role of T cells in this system.
    explanation: >-
      Rabbit TSST-1 mutant analysis showing that abolishing T cell receptor binding
      abolishes toxicity, establishing T cell activation as required rather than
      incidental. Model organism evidence, complementing the human clinical support.
- name: Systemic Cytokine Storm
  description: >-
    Simultaneous activation of T cells and antigen-presenting cells produces an
    overwhelming, self-amplifying release of proinflammatory cytokines including TNF,
    IL-1beta, IL-2 and IFN-gamma. This mediator burst, rather than bacterial invasion
    itself, produces the systemic illness; in staphylococcal TSS the organism is
    frequently confined to a colonized mucosal or wound surface.
  biological_scale: ORGANISM
  downstream:
  - target: Endothelial Injury and Capillary Leak
    description: >-
      Circulating cytokines act on vascular endothelium to increase permeability.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This results in a massive release of proinflammatory cytokines, with clinical
        signs, such as capillary leakage, arterial hypotension, organ failure, and
        coagulation activation, usually being reported in this setting
      explanation: >-
        Places capillary leakage downstream of the proinflammatory cytokine release,
        which is the transition this edge encodes.
  - target: Distributive Shock and Multi-Organ Dysfunction
    description: >-
      Cytokine-driven tissue damage and coagulation activation contribute directly to
      organ dysfunction.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Bacterial superantigenic exotoxins induces unconventional polyclonal lymphocyte
        activation, which leads to rapid shock, multiple organ failure syndrome, and
        death.
      explanation: >-
        Connects the superantigen-driven activation cascade to rapid shock and multiple
        organ failure, the endpoint this edge reaches.
  biological_processes:
  - preferred_term: cytokine production
    modifier: INCREASED
    term:
      id: GO:0001816
      label: cytokine production
  - preferred_term: tumor necrosis factor production
    modifier: INCREASED
    term:
      id: GO:0032640
      label: tumor necrosis factor production
  - preferred_term: interleukin-1 beta production
    modifier: INCREASED
    term:
      id: GO:0032611
      label: interleukin-1 beta production
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A repetitive cycle of cell stimulation and cytokine release results in a cytokine
      avalanche that causes tissue damage, disseminated intravascular coagulation, and
      organ dysfunction.
    explanation: >-
      Describes the self-amplifying cytokine cascade and links it to the tissue damage,
      coagulopathy and organ dysfunction this node feeds.
  - reference: PMID:33477467
    reference_title: "Toxic Shock Syndrome Toxin 1 Induces Immune Response via the Activation of NLRP3 Inflammasome."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      rTSST-1 significantly induced interleukin-1β (IL-1β) and tumor necrosis factor-α
      (TNF-α) production in mouse macrophages and the production was dose-dependent
    explanation: >-
      Macrophage stimulation experiments showing TSST-1 dose-dependently induces
      IL-1beta and TNF-alpha, supporting the innate-cell contribution to the cytokine
      burst. Marked PARTIAL because this is a murine macrophage system addressing one
      cellular contributor rather than the systemic human cytokine storm.
- name: Endothelial Injury and Capillary Leak
  description: >-
    Cytokine-driven endothelial activation, compounded by direct superantigen action on
    endothelial cells, causes upregulation of adhesion molecules, loss of monolayer
    barrier function, plasma extravasation into the interstitium, hypoalbuminemia and
    loss of effective intravascular volume.
  biological_scale: TISSUE
  downstream:
  - target: Distributive Shock and Multi-Organ Dysfunction
    description: >-
      Capillary leak plus cytokine-mediated vasodilation produces refractory
      hypotension.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        This results in a massive release of proinflammatory cytokines, with clinical
        signs, such as capillary leakage, arterial hypotension, organ failure, and
        coagulation activation, usually being reported in this setting
      explanation: >-
        Reports capillary leakage together with arterial hypotension and organ failure,
        supporting the progression from leak to shock this edge encodes.
  cell_types:
  - preferred_term: endothelial cell
    term:
      id: CL:0000115
      label: endothelial cell
  biological_processes:
  - preferred_term: regulation of vascular permeability
    modifier: INCREASED
    term:
      id: GO:0043114
      label: regulation of vascular permeability
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This results in a massive release of proinflammatory cytokines, with clinical
      signs, such as capillary leakage, arterial hypotension, organ failure, and
      coagulation activation, usually being reported in this setting
    explanation: >-
      Links the cytokine release directly to capillary leakage and arterial
      hypotension, the content of this node and the next.
  - reference: PMID:29229737
    reference_title: "The Superantigen Toxic Shock Syndrome Toxin 1 Alters Human Aortic Endothelial Cell Function."
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: >-
      TSST-1-mediated activation results in increased monolayer permeability and
      defects in vascular reendothelialization.
    explanation: >-
      Human aortic endothelial cell experiments showing the superantigen itself
      increases endothelial permeability, supporting a direct endothelial contribution
      to capillary leak alongside the cytokine-mediated route.
- name: Distributive Shock and Multi-Organ Dysfunction
  description: >-
    Refractory hypotension with tissue hypoperfusion, together with direct
    cytokine-mediated injury and coagulation activation, produces the multisystem
    failure that defines the syndrome: acute kidney injury, hepatic dysfunction,
    thrombocytopenia and disseminated intravascular coagulation, rhabdomyolysis, acute
    respiratory distress, and encephalopathy.
  biological_scale: ORGANISM
  biological_processes:
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Toxic shock syndrome (TSS) is an acute, multi-system, toxin-mediated illness,
      often resulting in multi-organ failure.
    explanation: >-
      Supports multi-organ failure as the terminal manifestation of the toxin-mediated
      cascade.
- name: Bacterial Ribosomal Translation (Clindamycin/Linezolid Target)
  description: >-
    Both causative organisms depend on 70S-ribosome translation. Clindamycin (a
    lincosamide) and linezolid (an oxazolidinone) bind the 50S subunit and arrest
    bacterial protein synthesis. In TSS this target is pursued not primarily for
    bacterial killing, which the beta-lactam provides, but because the superantigens
    are themselves translated products.
  biological_scale: MOLECULAR
  role: therapeutic_vulnerability
  conforms_to: "bacterial_protein_synthesis_inhibition#Bacterial mRNA Translation by the Ribosome"
  biological_processes:
  - preferred_term: translation
    term:
      id: GO:0006412
      label: translation
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Specific therapy focuses on early identification of the illness, source control,
      and administration on antimicrobial agents including drugs capable of suppressing
      toxin production (eg, clindamycin, linezolid).
    explanation: >-
      Identifies clindamycin and linezolid, both ribosome-targeting protein synthesis
      inhibitors, as the specific agents used in TSS therapy.
- name: Suppression of Superantigen Synthesis by Protein-Synthesis Inhibitors
  description: >-
    Because TSST-1 and the streptococcal pyrogenic exotoxins are secreted proteins, a
    ribosome-targeting antibiotic suppresses their production independently of
    bacterial killing. This anti-toxin rationale is why clindamycin is added to a
    bactericidal beta-lactam in TSS rather than used as a substitute for it, and it is
    the mechanistic basis for the observed mortality association with adjunctive
    clindamycin in streptococcal disease.
  biological_scale: MOLECULAR
  role: therapeutic_vulnerability
  conforms_to: "bacterial_protein_synthesis_inhibition#Suppression of Toxin and Exoprotein Synthesis"
  biological_processes:
  - preferred_term: translation
    modifier: DECREASED
    term:
      id: GO:0006412
      label: translation
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Specific therapy focuses on early identification of the illness, source control,
      and administration on antimicrobial agents including drugs capable of suppressing
      toxin production (eg, clindamycin, linezolid).
    explanation: >-
      Explicitly frames clindamycin and linezolid as agents capable of suppressing
      toxin production, which is the step this node represents.
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management of TSS is a medical emergency and relies on early detection, immediate
      resuscitation, source control and eradication of toxin production, bactericidal
      antibiotic treatment, and protein synthesis inhibiting antibiotic administration.
    explanation: >-
      Separates eradication of toxin production and protein-synthesis-inhibiting
      therapy from bactericidal therapy, matching the distinction between this node and
      the peptidoglycan cross-linking node.
- name: Ribosomal Target Resistance in Group A Streptococcus
  description: >-
    The anti-toxin rationale for adjunctive clindamycin is contingent on the organism
    remaining susceptible to it. Ribosomal-target resistance, principally erm-mediated
    rRNA methylation, is rising sharply in invasive group A Streptococcus: isolates
    non-susceptible to macrolides and clindamycin went from 12.7% to 33.1% over a
    decade of US surveillance. This is a direct and growing threat to the
    toxin-suppression step above, and is why susceptibility testing now gates the
    adjunct.
  biological_scale: MOLECULAR
  role: adaptive_escape
  conforms_to: "bacterial_protein_synthesis_inhibition#Ribosomal Target Resistance"
  biological_processes:
  - preferred_term: response to antibiotic
    modifier: INCREASED
    term:
      id: GO:0046677
      label: response to antibiotic
  evidence:
  - reference: PMID:40193120
    reference_title: "Invasive Group A Streptococcal Infections in 10 US States."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Among tested isolates, those nonsusceptible to macrolides and clindamycin
      increased from 12.7% in 2013 to 33.1% in 2022.
    explanation: >-
      Population-based surveillance quantifying the rise in clindamycin
      non-susceptibility among invasive group A streptococcal isolates, the resistance
      step this node represents.
- name: Bacterial Peptidoglycan Cross-Linking (Beta-Lactam Target)
  description: >-
    Both Staphylococcus aureus and Streptococcus pyogenes build the peptidoglycan cell
    wall by penicillin-binding protein transpeptidase cross-linking. Beta-lactam
    acylation of the PBP active site halts cross-linking and is bactericidal. This is
    the target of the antistaphylococcal penicillin or cefazolin used for
    methicillin-susceptible staphylococcal TSS and of the penicillin used for
    streptococcal TSS; methicillin-resistant strains express an altered PBP and require
    vancomycin or linezolid instead.
  biological_scale: MOLECULAR
  role: therapeutic_vulnerability
  conforms_to: "bacterial_cell_wall_synthesis_inhibition#Peptidoglycan Cross-Linking by Penicillin-Binding Proteins"
  biological_processes:
  - preferred_term: peptidoglycan-based cell wall biogenesis
    term:
      id: GO:0009273
      label: peptidoglycan-based cell wall biogenesis
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management of TSS is a medical emergency and relies on early detection, immediate
      resuscitation, source control and eradication of toxin production, bactericidal
      antibiotic treatment, and protein synthesis inhibiting antibiotic administration.
    explanation: >-
      Establishes bactericidal antibiotic treatment as a distinct required component of
      TSS management; the beta-lactam PBP target is the step this node represents.
phenotypes:
- category: Constitutional
  name: Fever
  description: >-
    Abrupt high fever, conventionally a temperature of 38.9 degrees Celsius or higher,
    is one of the five required clinical criteria in the case definition.
  phenotype_term:
    preferred_term: Fever
    term:
      id: HP:0001945
      label: Fever
    temporality: ACUTE
  diagnostic: true
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis was confirmed by fulfilment of the clinical criteria outlined by
      the US Centers for Disease Control and Prevention (CDC; fever, rash,
      desquamation, hypotension, and multi-system involvement)
    explanation: >-
      Fever is enumerated as one of the required CDC clinical criteria, supporting both
      its presence and its diagnostic role. No frequency band is asserted: because this
      is a required criterion, its rate among confirmed cases is an ascertainment
      artifact rather than a measured frequency.
- category: Cardiovascular
  name: Hypotension
  description: >-
    Refractory hypotension, defined in adults as a systolic blood pressure at or below
    90 mmHg, defines the shock state and is a required clinical criterion.
  phenotype_term:
    preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
    temporality: ACUTE
  diagnostic: true
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis was confirmed by fulfilment of the clinical criteria outlined by
      the US Centers for Disease Control and Prevention (CDC; fever, rash,
      desquamation, hypotension, and multi-system involvement)
    explanation: >-
      Hypotension is enumerated as a required CDC clinical criterion.
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      This results in a massive release of proinflammatory cytokines, with clinical
      signs, such as capillary leakage, arterial hypotension, organ failure, and
      coagulation activation, usually being reported in this setting
    explanation: >-
      Connects arterial hypotension mechanistically to the cytokine release cascade.
- category: Skin
  name: Diffuse Macular Erythroderma
  description: >-
    A diffuse, blanching, sunburn-like macular erythroderma involving the trunk and
    extremities, appearing early in the illness.
  phenotype_term:
    preferred_term: Diffuse macular erythroderma
    term:
      id: HP:0001019
      label: Erythroderma
    temporality: ACUTE
  diagnostic: true
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis was confirmed by fulfilment of the clinical criteria outlined by
      the US Centers for Disease Control and Prevention (CDC; fever, rash,
      desquamation, hypotension, and multi-system involvement)
    explanation: >-
      Rash is a required CDC clinical criterion. The preferred_term records the
      characteristic diffuse macular erythroderma, more specific than the bound HPO
      parent term.
- category: Skin
  name: Palmoplantar Desquamation
  description: >-
    Full-thickness desquamation, classically of the palms and soles, occurring one to
    two weeks after the onset of the rash. It is a required criterion for a confirmed
    case and is therefore a late, convalescent-phase finding rather than a presenting
    sign.
  phenotype_term:
    preferred_term: Palmoplantar desquamation
    term:
      id: HP:0025524
      label: Palmoplantar scaling skin
  diagnostic: true
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis was confirmed by fulfilment of the clinical criteria outlined by
      the US Centers for Disease Control and Prevention (CDC; fever, rash,
      desquamation, hypotension, and multi-system involvement)
    explanation: >-
      Desquamation is enumerated as a required CDC clinical criterion. The bound HPO
      term describes palmoplantar scaling; preferred_term retains the clinical
      desquamation phrasing.
  - reference: PMID:32461307
    reference_title: "Device-Associated Menstrual Toxic Shock Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      During convalescence, four girls and three boys had desquamation of the affected
      skin and peeling of the palms and soles of their feet.
    explanation: >-
      The index case series describes palmoplantar desquamation directly, and places it
      in convalescence, matching the late timing recorded in this phenotype.
- category: Head and neck
  name: Strawberry Tongue
  description: >-
    Mucous membrane involvement includes strawberry tongue and oropharyngeal hyperemia,
    part of the mucous-membrane organ system in the multisystem criterion.
  phenotype_term:
    preferred_term: Strawberry tongue
    term:
      id: HP:0031042
      label: Strawberry tongue
  evidence:
  - reference: PMID:33304729
    reference_title: "Chronological changes in strawberry tongue in toxic shock syndrome toxin-1-mediated Exanthematous Disease."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Strawberry tongue is a useful diagnostic feature in various diseases such as
      Kawasaki disease, TSS, scarlet fever, and group A streptococcal pharyngitis.
    explanation: >-
      Names strawberry tongue as a diagnostic feature of TSS directly, replacing the
      earlier inference from its occurrence in scarlet fever.
- category: Eye
  name: Conjunctival Hyperemia
  description: >-
    Non-purulent conjunctival hyperemia is one of the mucous-membrane findings counted
    toward multisystem involvement.
  phenotype_term:
    preferred_term: Conjunctival hyperemia
    term:
      id: HP:0030953
      label: Conjunctival hyperemia
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The authors described a pediatric case series of seven children, with clinical
      presentations including high fever, cephalalgia, confusion, cutaneous rash,
      conjunctival hyperhemia, and digestive signs.
    explanation: >-
      The index case series describing TSS names conjunctival hyperaemia directly among
      the presenting features. Quoted verbatim, including the source's spelling
      "hyperhemia".
- category: Gastrointestinal
  name: Vomiting
  description: >-
    Vomiting at illness onset is one of the gastrointestinal findings counted toward
    the multisystem-involvement criterion.
  phenotype_term:
    preferred_term: Vomiting
    term:
      id: HP:0002013
      label: Vomiting
    temporality: ACUTE
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Digestive signs (abdominal pain, diarrhea, and vomiting) and cephalalgia were
      very common
    explanation: >-
      A 102-case multicentre series of menstrual TSS naming vomiting directly and
      reporting it as very common.
  - reference: PMID:40711134
    reference_title: "Toxic Shock Syndrome Toxin-1 (TSST-1) in Staphylococcus aureus: Prevalence, Molecular Mechanisms, and Public Health Implications."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: >-
      This loop is responsible for the gastrointestinal toxicity observed with SEB,
      including its ability to induce vomiting, a feature not shared by TSST-1.
    explanation: >-
      Attributes the emetic component of staphylococcal TSS to the enterotoxins' emetic
      cystine loop rather than to TSST-1, which lacks it. Evidence source is OTHER as
      this is a structural/mechanistic review.
  notes: >-
    Gastrointestinal toxicity in staphylococcal TSS traces to the staphylococcal
    enterotoxins rather than to TSST-1, which lacks the emetic cystine loop.
- category: Gastrointestinal
  name: Diarrhea
  description: >-
    Watery diarrhea at illness onset, alongside vomiting, forms the gastrointestinal
    component of the multisystem criterion.
  phenotype_term:
    preferred_term: Diarrhea
    term:
      id: HP:0002014
      label: Diarrhea
    temporality: ACUTE
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Digestive signs (abdominal pain, diarrhea, and vomiting) and cephalalgia were
      very common
    explanation: >-
      A 102-case multicentre series of menstrual TSS naming diarrhea directly and
      reporting it as very common.
  - reference: PMID:32461307
    reference_title: "Device-Associated Menstrual Toxic Shock Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In 1978, Todd et al. (4) identified an acute, severe illness characterized by
      high fever, generalized skin rash, conjunctival hyperemia, diarrhea, hypotension,
      and renal failure in seven children (8 to 17 years of age).
    explanation: >-
      The index description of TSS names diarrhea among the defining features.
- category: Musculoskeletal
  name: Myositis
  description: >-
    Muscle involvement forms the muscular component of the multisystem criterion,
    clinically spanning severe myalgia through frank myositis with rhabdomyolysis and
    creatine kinase elevation. Only the myositis end of that range is backed by an
    enumerating source in the current reference set, so that is what this phenotype
    asserts; see the entry notes.
  phenotype_term:
    preferred_term: Myositis
    term:
      id: HP:0100614
      label: Myositis
  subtype: Streptococcal TSS
  evidence:
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clinical evidence of STSS included hypotension and at least two of the following:
      renal impairment, coagulopathy, liver function abnormality, acute respiratory
      distress syndrome, generalised erythematous macular rash (with desquamation),
      soft-tissue necrosis (including necrotising fasciitis, myositis or gangrene) or
      meningitis.
    explanation: >-
      The STSS case-ascertainment criteria used by this systematic review name myositis
      explicitly among the qualifying organ manifestations.
- category: Renal
  name: Acute Kidney Injury
  description: >-
    Acute kidney injury with urea and creatinine elevated to at least twice the upper
    limit of normal is the renal component of multisystem involvement and is often one
    of the earliest organ derangements.
  phenotype_term:
    preferred_term: Acute kidney injury
    term:
      id: HP:0001919
      label: Acute kidney injury
    temporality: ACUTE
  evidence:
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clinical evidence of STSS included hypotension and at least two of the following:
      renal impairment, coagulopathy, liver function abnormality, acute respiratory
      distress syndrome, generalised erythematous macular rash (with desquamation),
      soft-tissue necrosis (including necrotising fasciitis, myositis or gangrene) or
      meningitis.
    explanation: >-
      Renal impairment is named explicitly among the qualifying organ manifestations in
      the STSS case-ascertainment criteria.
  - reference: PMID:32461307
    reference_title: "Device-Associated Menstrual Toxic Shock Syndrome."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In 1978, Todd et al. (4) identified an acute, severe illness characterized by
      high fever, generalized skin rash, conjunctival hyperemia, diarrhea, hypotension,
      and renal failure in seven children (8 to 17 years of age).
    explanation: >-
      The index description of TSS names renal failure among the defining features,
      supporting renal involvement in the staphylococcal form as well.
- category: Hematologic
  name: Thrombocytopenia
  description: >-
    A platelet count below 100,000 per cubic millimetre is the hematologic component of
    the multisystem criterion.
  phenotype_term:
    preferred_term: Thrombocytopenia
    term:
      id: HP:0001873
      label: Thrombocytopenia
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A repetitive cycle of cell stimulation and cytokine release results in a cytokine
      avalanche that causes tissue damage, disseminated intravascular coagulation, and
      organ dysfunction.
    explanation: >-
      Supports cytokine-driven consumptive coagulopathy, of which thrombocytopenia is
      the corresponding count abnormality. Marked PARTIAL because the snippet names
      disseminated intravascular coagulation rather than the platelet count itself.
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clinical evidence of STSS included hypotension and at least two of the following:
      renal impairment, coagulopathy, liver function abnormality, acute respiratory
      distress syndrome, generalised erythematous macular rash (with desquamation),
      soft-tissue necrosis (including necrotising fasciitis, myositis or gangrene) or
      meningitis.
    explanation: >-
      Coagulopathy is a qualifying organ manifestation in the STSS criteria. Marked
      PARTIAL because the criteria name coagulopathy rather than the platelet threshold
      this phenotype records.
- category: Hematologic
  name: Disseminated Intravascular Coagulation
  description: >-
    Consumptive coagulopathy with prolonged clotting times, hypofibrinogenemia and
    raised fibrin degradation products, driven by the cytokine storm.
  phenotype_term:
    preferred_term: Disseminated intravascular coagulation
    term:
      id: HP:0005521
      label: Disseminated intravascular coagulation
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      A repetitive cycle of cell stimulation and cytokine release results in a cytokine
      avalanche that causes tissue damage, disseminated intravascular coagulation, and
      organ dysfunction.
    explanation: >-
      Directly names disseminated intravascular coagulation as a consequence of the
      cytokine cascade in TSS.
- category: Neurologic
  name: Confusion
  description: >-
    Disorientation or altered consciousness without focal neurological signs is the
    central nervous system component of the multisystem criterion.
  phenotype_term:
    preferred_term: Confusion
    term:
      id: HP:0001289
      label: Confusion
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The authors described a pediatric case series of seven children, with clinical
      presentations including high fever, cephalalgia, confusion, cutaneous rash,
      conjunctival hyperhemia, and digestive signs.
    explanation: >-
      The index TSS case series names confusion directly among the presenting features.
- category: Hepatic
  name: Elevated Transaminases
  description: >-
    Bilirubin or transaminases elevated to at least twice the upper limit of normal
    constitute the hepatic component of multisystem involvement.
  phenotype_term:
    preferred_term: Elevated circulating aspartate aminotransferase concentration
    term:
      id: HP:0031956
      label: Elevated circulating aspartate aminotransferase concentration
  evidence:
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clinical evidence of STSS included hypotension and at least two of the following:
      renal impairment, coagulopathy, liver function abnormality, acute respiratory
      distress syndrome, generalised erythematous macular rash (with desquamation),
      soft-tissue necrosis (including necrotising fasciitis, myositis or gangrene) or
      meningitis.
    explanation: >-
      Liver function abnormality is named explicitly among the qualifying organ
      manifestations in the STSS case-ascertainment criteria.
- category: Respiratory
  name: Acute Respiratory Distress Syndrome
  description: >-
    Acute respiratory distress syndrome is one of the organ dysfunctions counted in the
    streptococcal TSS case definition.
  phenotype_term:
    preferred_term: Acute respiratory distress syndrome
    term:
      id: HP:0033677
      label: Acute respiratory distress syndrome
    temporality: ACUTE
  subtype: Streptococcal TSS
  evidence:
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clinical evidence of STSS included hypotension and at least two of the following:
      renal impairment, coagulopathy, liver function abnormality, acute respiratory
      distress syndrome, generalised erythematous macular rash (with desquamation),
      soft-tissue necrosis (including necrotising fasciitis, myositis or gangrene) or
      meningitis.
    explanation: >-
      Acute respiratory distress syndrome is named explicitly among the qualifying
      organ manifestations in the STSS case-ascertainment criteria.
- category: Skin
  name: Necrotizing Soft Tissue Infection
  description: >-
    Deep soft tissue necrosis, typically necrotizing fasciitis, is the characteristic
    portal of infection in streptococcal TSS and both drives the syndrome and demands
    emergent surgical debridement. It is not a feature of staphylococcal TSS, where the
    organism usually remains at a colonized surface.
  phenotype_term:
    preferred_term: Necrotizing fasciitis
    term:
      id: HP:0100537
      label: Fasciitis
  subtype: Streptococcal TSS
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Streptococcal TSS is linked to a severe group A streptococcal infection and,
      most frequently, to a necrotizing soft tissue infection.
    explanation: >-
      Directly associates necrotizing soft tissue infection with streptococcal TSS. HPO
      has no necrotizing-fasciitis term, so the parent Fasciitis is bound and the
      specific clinical entity is carried in preferred_term.
clinical_trials:
- name: NCT02340338
  phase: PHASE_I
  status: COMPLETED
  description: >-
    First-in-human, randomised, double-blind, adjuvant-controlled dose-escalation trial
    of the recombinant detoxified TSST-1 variant vaccine in 46 healthy adults, assessing
    safety, tolerability and anti-TSST-1 antibody response. Reported in PMID:27296693.
  target_phenotypes:
  - preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
  evidence:
  - reference: clinicaltrials:NCT02340338
    reference_title: "Phase 1 Clinical Trial of the BioMed rTSST-1 Variant Vaccine in Healthy Adults"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The aim of this study is to demonstrate the safety and tolerability of the BioMed
      recombinant toxic shock syndrome toxin (rTSST-1) Variant Vaccine in healthy
      adults.
    explanation: >-
      Trial registry record for the rTSST-1v vaccine curated in the treatments section,
      confirming its phase, design and objective.
  - reference: clinicaltrials:NCT02340338
    reference_title: "Phase 1 Clinical Trial of the BioMed rTSST-1 Variant Vaccine in Healthy Adults"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Toxic shock syndrome toxin (TSST-1) being responsible for almost all of
      menstruation associated and more than 50% of all other cases.
    explanation: >-
      Quantifies why TSST-1 is the vaccine target: it accounts for nearly all menstrual
      and over half of non-menstrual staphylococcal TSS.
genetic:
- name: HLA-DRB1
  association: >-
    HLA class II genotype is the best-characterized human genetic modifier of TSS
    susceptibility. It does not cause disease directly; it sets the magnitude of the
    anti-TSST-1 antibody response, and therefore whether a host can neutralize the
    superantigen on exposure. HLA-DRB1*03:01 is positively associated with anti-TSST-1
    antibody levels, whereas HLA-DRB1*01:01 is negatively associated.
  gene_term:
    preferred_term: HLA-DRB1
    term:
      id: hgnc:4948
      label: HLA-DRB1
  relationship_type: SUSCEPTIBILITY
  evidence:
  - reference: PMID:37731490
    reference_title: "Toxin exposure and HLA alleles determine serum antibody binding to toxic shock syndrome toxin 1 (TSST-1) of Staphylococcus aureus."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Moreover, the anti-TSST-1 antibody levels were strongly associated with HLA class
      II gene loci.
    explanation: >-
      Genome-wide association analysis in 976 population-based participants showing HLA
      class II loci govern the anti-TSST-1 antibody response that determines
      susceptibility.
- name: HLA-DQB1
  association: >-
    HLA-DQB1*02:01 is positively and HLA-DQB1*05:01 negatively associated with
    anti-TSST-1 antibody levels, acting with HLA-DRB1 as a susceptibility modifier
    through the humoral antitoxin response rather than through any direct disease
    mechanism.
  gene_term:
    preferred_term: HLA-DQB1
    term:
      id: hgnc:4944
      label: HLA-DQB1
  relationship_type: SUSCEPTIBILITY
  evidence:
  - reference: PMID:37731490
    reference_title: "Toxin exposure and HLA alleles determine serum antibody binding to toxic shock syndrome toxin 1 (TSST-1) of Staphylococcus aureus."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Moreover, the anti-TSST-1 antibody levels were strongly associated with HLA class
      II gene loci.
    explanation: >-
      Same population-based genetic analysis identifying HLA class II loci, including
      HLA-DQB1, as determinants of the protective antibody response.
definitions:
- name: CDC clinical case definition for toxic shock syndrome
  definition_type: CASE_DEFINITION
  derivation_basis: ESTABLISHED_CRITERIA
  description: >-
    The US Centers for Disease Control and Prevention case definition for staphylococcal
    TSS requires fever, a diffuse macular erythroderma, desquamation one to two weeks
    after rash onset, hypotension, and involvement of at least three organ systems from
    the gastrointestinal, muscular, mucous-membrane, renal, hepatic, hematologic and
    central nervous system categories. Because desquamation appears only during
    convalescence, a confirmed case is often only assignable retrospectively, which
    limits the definition's usefulness at the bedside.
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      The diagnosis was confirmed by fulfilment of the clinical criteria outlined by
      the US Centers for Disease Control and Prevention (CDC; fever, rash,
      desquamation, hypotension, and multi-system involvement)
    explanation: >-
      Enumerates the five CDC clinical criteria that constitute this case definition.
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      the CDC criteria have appreciable limitations in everyday clinical practice.
    explanation: >-
      Supports the recorded caveat that the case definition, designed for surveillance,
      performs imperfectly as a bedside diagnostic instrument.
diagnosis:
- name: Culture of the suspected focus and sterile sites
  description: >-
    Blood, wound, and mucosal-site cultures are obtained. In streptococcal TSS
    Streptococcus pyogenes is frequently recovered from a normally sterile site, which
    is required for a confirmed case; in staphylococcal TSS blood cultures are often
    negative because the organism remains at a colonized surface while the toxin acts
    systemically.
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: NCIT:C18020
      label: Diagnostic Procedure
  results: >-
    Isolation of a superantigen-producing Staphylococcus aureus or Streptococcus
    pyogenes strain in a compatible clinical syndrome.
  evidence:
  - reference: PMID:31151811
    reference_title: "Menstrual toxic shock syndrome: case report and systematic review of the literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      as well as a nasal swab positive for the S aureus strain and presence of the gene
      encoding for toxic shock syndrome toxin 1 (TSST-1).
    explanation: >-
      Illustrates microbiological confirmation by recovery of the organism together with
      demonstration of the toxin gene.
treatments:
- name: Source control
  description: >-
    Immediate removal of the inciting focus: withdrawal of a retained tampon, nasal
    packing or other foreign body, and emergent surgical debridement of infected or
    necrotic soft tissue in streptococcal disease. Source control removes the site of
    ongoing toxin elaboration and is repeatedly identified as one of the principal
    modifiable determinants of survival.
  treatment_term:
    preferred_term: surgical procedure
    term:
      id: NCIT:C15329
      label: Surgical Procedure
  therapeutic_modality: SURGERY
  target_mechanisms:
  - target: Superantigen Exotoxin Production
    description: >-
      Removing the colonized device or debriding necrotic tissue eliminates the niche in
      which superantigen is being produced.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        source control and eradication of toxin production
      explanation: >-
        Pairs source control directly with eradication of toxin production, the
        mechanism node this treatment targets.
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management of TSS is a medical emergency and relies on early detection, immediate
      resuscitation, source control and eradication of toxin production, bactericidal
      antibiotic treatment, and protein synthesis inhibiting antibiotic administration.
    explanation: >-
      Lists source control and eradication of toxin production as core components of
      emergency TSS management.
- name: Bactericidal beta-lactam antibiotic therapy
  description: >-
    A bactericidal agent directed at the causative organism: penicillin for group A
    Streptococcus, and an antistaphylococcal penicillin or cefazolin for
    methicillin-susceptible Staphylococcus aureus. Vancomycin or linezolid replaces the
    beta-lactam when methicillin resistance is present or suspected empirically.
  treatment_term:
    preferred_term: antibiotic therapy
    term:
      id: NCIT:C15620
      label: Antibiotic Therapy
    therapeutic_agent:
    - preferred_term: penicillin
      term:
        id: CHEBI:17334
        label: penicillin
    - preferred_term: vancomycin
      term:
        id: CHEBI:28001
        label: vancomycin
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Bacterial Peptidoglycan Cross-Linking (Beta-Lactam Target)
    description: >-
      Beta-lactams acylate the penicillin-binding protein transpeptidase and halt
      peptidoglycan cross-linking, killing the organism.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Management of TSS is a medical emergency and relies on early detection,
        immediate resuscitation, source control and eradication of toxin production,
        bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic
        administration.
      explanation: >-
        Establishes bactericidal antibiotic therapy as a component of TSS management.
        Marked PARTIAL because the review states the clinical role rather than the
        penicillin-binding-protein mechanism, which is carried on the target node.
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management of TSS is a medical emergency and relies on early detection, immediate
      resuscitation, source control and eradication of toxin production, bactericidal
      antibiotic treatment, and protein synthesis inhibiting antibiotic administration.
    explanation: >-
      Establishes bactericidal antibiotic therapy as a required, distinct component of
      TSS management.
- name: Adjunctive protein-synthesis-inhibiting antibiotic therapy
  description: >-
    Clindamycin, or linezolid where clindamycin cannot be used, is added to the
    bactericidal agent specifically to suppress superantigen synthesis. In invasive
    beta-haemolytic streptococcal infection adjunctive clindamycin added to a beta-lactam
    is associated with lower mortality, and in streptococcal TSS specifically a
    meta-analysis found a significant association between clindamycin treatment and
    reduced mortality, although the certainty of that evidence was rated low.
  treatment_term:
    preferred_term: antibiotic therapy
    term:
      id: NCIT:C15620
      label: Antibiotic Therapy
    therapeutic_agent:
    - preferred_term: clindamycin
      term:
        id: CHEBI:3745
        label: clindamycin
    - preferred_term: linezolid
      term:
        id: CHEBI:63607
        label: linezolid
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Bacterial Ribosomal Translation (Clindamycin/Linezolid Target)
    description: >-
      Clindamycin and linezolid bind the 50S ribosomal subunit and arrest bacterial
      protein synthesis.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        protein synthesis inhibiting antibiotic administration
      explanation: >-
        Names protein-synthesis inhibition as the therapeutic action, which is the
        bacterial translation target this link points to.
  - target: Suppression of Superantigen Synthesis by Protein-Synthesis Inhibitors
    description: >-
      Arresting translation suppresses production of the secreted superantigen driving
      the syndrome, independently of bacterial killing.
    evidence:
    - reference: PMID:19393958
      reference_title: "Gram-positive toxic shock syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        drugs capable of suppressing toxin production (eg, clindamycin, linezolid)
      explanation: >-
        Names clindamycin and linezolid specifically as toxin-production-suppressing
        drugs, which is the mechanism node this link targets.
  evidence:
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Specific therapy focuses on early identification of the illness, source control,
      and administration on antimicrobial agents including drugs capable of suppressing
      toxin production (eg, clindamycin, linezolid).
    explanation: >-
      Names clindamycin and linezolid as the toxin-suppressing agents used in TSS.
  - reference: PMID:36456018
    reference_title: "Prognostic factors for streptococcal toxic shock syndrome: systematic review and meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We found a statistically significant association between clindamycin treatment
      and mortality
    explanation: >-
      Meta-analysis reporting a significant clindamycin-mortality association in
      streptococcal TSS; the authors' own low-certainty caveat is preserved in the
      treatment description.
  - reference: PMID:33333013
    reference_title: "Effectiveness of adjunctive clindamycin in β-lactam antibiotic-treated patients with invasive β-haemolytic streptococcal infections in US hospitals: a retrospective multicentre cohort study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Clindamycin is strongly recommended as an adjunctive treatment to β-lactam
      antibiotics in patients with severe invasive group A β-haemolytic streptococcal
      (iGAS) infections.
    explanation: >-
      States the guideline position on adjunctive clindamycin in invasive group A
      streptococcal infection. Marked PARTIAL because the cohort addresses invasive
      streptococcal infection broadly rather than toxic shock syndrome specifically.
- name: Intravenous immunoglobulin
  description: >-
    High-dose polyspecific intravenous immunoglobulin is used as an adjunct on the
    rationale that pooled donor immunoglobulin contains neutralizing antibody against
    the superantigen, supplying the antitoxin the host lacks. The evidence is genuinely
    contested: a meta-analysis restricted to clindamycin-treated streptococcal TSS found
    mortality fell from 33.7% to 15.7%, whereas a Japanese nationwide observational
    study of invasive group A streptococcal infection found no adjusted survival
    benefit. See the recorded discussion on this conflict.
  treatment_term:
    preferred_term: intravenous immunoglobulin therapy
    term:
      id: NCIT:C121331
      label: Intravenous Immunoglobulin Therapy
  therapeutic_modality: OTHER
  target_mechanisms:
  - target: Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking
    description: >-
      Pooled immunoglobulin is proposed to neutralize circulating superantigen before it
      can bridge MHC class II and the T cell receptor.
    evidence:
    - reference: PMID:19393958
      reference_title: "Gram-positive toxic shock syndromes."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Intravenous immunoglobulin has the potential to neutralise superantigen and to
        mitigate subsequent tissue damage.
      explanation: >-
        States the superantigen-neutralization mechanism, which is the cross-linking
        node this link targets.
  evidence:
  - reference: PMID:29788397
    reference_title: "Polyspecific Intravenous Immunoglobulin in Clindamycin-treated Patients With Streptococcal Toxic Shock Syndrome: A Systematic Review and Meta-analysis."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      In association with IVIG, mortality fell from 33.7% to 15.7% with remarkable
      consistency across the single randomized and four nonrandomized studies.
    explanation: >-
      Meta-analysis in clindamycin-treated streptococcal TSS reporting a mortality
      reduction associated with IVIG.
  - reference: PMID:37586661
    reference_title: "Effectiveness of intravenous immunoglobulin therapy for invasive group A Streptococcus infection: A Japanese nationwide observational study."
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      IVIG administration had no survival benefit in iGAS patients.
    explanation: >-
      Nationwide observational cohort of 481 patients finding no adjusted mortality
      benefit of IVIG, directly opposing the meta-analytic estimate. Retained as REFUTE
      so the conflict is visible rather than resolved by curator preference.
  - reference: PMID:19393958
    reference_title: "Gram-positive toxic shock syndromes."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Intravenous immunoglobulin has the potential to neutralise superantigen and to
      mitigate subsequent tissue damage.
    explanation: >-
      States the superantigen-neutralization rationale that motivates the
      target_mechanisms link.
- name: Fluid resuscitation and vasopressor support
  description: >-
    Aggressive intravenous crystalloid resuscitation to replace the volume lost to
    capillary leak, followed by vasopressors for fluid-refractory shock, together with
    intensive-care organ support.
  treatment_term:
    preferred_term: supportive care
    term:
      id: NCIT:C15747
      label: Supportive Care
  therapeutic_modality: OTHER
  target_mechanisms:
  - target: Distributive Shock and Multi-Organ Dysfunction
    description: >-
      Volume replacement and vasopressors counter the distributive shock produced by
      capillary leak and vasodilation, without addressing the toxin itself.
    evidence:
    - reference: PMID:38247655
      reference_title: "Toxic Shock Syndrome: A Literature Review."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        Management of TSS is a medical emergency and relies on early detection,
        immediate resuscitation, source control and eradication of toxin production,
        bactericidal antibiotic treatment, and protein synthesis inhibiting antibiotic
        administration.
      explanation: >-
        Establishes immediate resuscitation as a required management step. Marked
        PARTIAL because it is supportive rather than mechanism-directed therapy, so the
        link is to the shock node it counteracts rather than to a drug target.
  target_phenotypes:
  - preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
  evidence:
  - reference: PMID:38247655
    reference_title: "Toxic Shock Syndrome: A Literature Review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Management of TSS is a medical emergency and relies on early detection, immediate
      resuscitation, source control and eradication of toxin production, bactericidal
      antibiotic treatment, and protein synthesis inhibiting antibiotic administration.
    explanation: >-
      Lists immediate resuscitation as a core component of emergency TSS management.
- name: Recombinant detoxified TSST-1 variant vaccine
  description: >-
    An investigational active-immunoprophylaxis approach targeting the core superantigen
    mechanism directly. A recombinant detoxified TSST-1 variant (rTSST-1v) was safe and
    immunogenic in a first-in-human dose-escalation trial. It is not licensed, and no
    efficacy against clinical TSS has been demonstrated.
  treatment_term:
    preferred_term: vaccination
    term:
      id: NCIT:C15346
      label: Vaccination
  therapeutic_modality: VACCINE
  target_mechanisms:
  - target: Absent or Low Neutralizing Antitoxin Antibody
    description: >-
      Active immunization is intended to induce the neutralizing antitoxin antibody
      whose absence is the principal host susceptibility factor.
    evidence:
    - reference: PMID:27296693
      reference_title: "Safety, tolerability, and immunogenicity of a recombinant toxic shock syndrome toxin (rTSST)-1 variant vaccine: a randomised, double-blind, adjuvant-controlled, dose escalation first-in-man trial."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: >-
        We aimed to assess the safety, tolerability, and immunogenicity of a recombinant
        detoxified toxic shock syndrome toxin-1 variant (rTSST-1v) vaccine in adult
        volunteers.
      explanation: >-
        The trial's immunogenicity endpoint is the antitoxin antibody response this link
        targets. Marked PARTIAL because immunogenicity in volunteers is not
        demonstrated protection against clinical TSS.
  evidence:
  - reference: PMID:27296693
    reference_title: "Safety, tolerability, and immunogenicity of a recombinant toxic shock syndrome toxin (rTSST)-1 variant vaccine: a randomised, double-blind, adjuvant-controlled, dose escalation first-in-man trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      We aimed to assess the safety, tolerability, and immunogenicity of a recombinant
      detoxified toxic shock syndrome toxin-1 variant (rTSST-1v) vaccine in adult
      volunteers.
    explanation: >-
      Establishes the existence and objective of the first-in-human rTSST-1v vaccine
      trial.
  - reference: PMID:27296693
    reference_title: "Safety, tolerability, and immunogenicity of a recombinant toxic shock syndrome toxin (rTSST)-1 variant vaccine: a randomised, double-blind, adjuvant-controlled, dose escalation first-in-man trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      Staphylococcal toxic shock syndrome is a superantigen-driven potentially
      life-threatening disease affecting mainly young and otherwise healthy
      individuals. Currently, no specific treatment or preventive measure is available.
    explanation: >-
      Supports the recorded caveat that no licensed specific preventive measure exists,
      which is why this entry is curated as investigational.
animal_models:
- name: Rabbit superantigen challenge model
  species: Rabbit
  genotype: Wild type
  description: >-
    The rabbit is the standard experimental model for TSS because its sensitivity to
    staphylococcal and streptococcal superantigens is comparable to that of humans,
    unlike wild-type mice whose MHC class II binds these toxins poorly. Challenge with
    TSST-1 and structure-guided mutants was used to dissect which binding interface
    drives toxicity.
  publication: PMID:22069685
  evidence:
  - reference: PMID:22069685
    reference_title: "Staphylococcal superantigen (TSST-1) mutant analysis reveals that t cell activation is required for biological effects in the rabbit including the cytokine storm."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: >-
      Staphylococcal superantigens (sAgs), such as toxic shock syndrome toxin 1
      (TSST-1), induce massive cytokine production, which may result in toxic shock
      syndrome (TSS) and sepsis.
    explanation: >-
      Establishes that the superantigen challenge this model administers reproduces the
      massive cytokine production underlying toxic shock syndrome, which is what makes
      the model informative for the disease.
  modeled_mechanisms:
  - target: Massive Polyclonal T Cell Activation
    relationship: PERTURBS
    fidelity: MODERATE
    description: >-
      Comparison of a TSST-1 mutant with reduced MHC binding against one with abolished
      T cell receptor binding isolates the T cell activation step and shows it is
      required for the toxic phenotype.
    limitations: >-
      The model delivers purified toxin by direct challenge rather than reproducing
      toxin elaboration by a colonizing organism, and does not capture the human
      menstrual or wound microenvironment in which superantigen is naturally produced.
      Co-treatment with lipopolysaccharide is used to elicit the full inflammatory
      response.
    readouts:
    - name: Lymphocyte proliferation and IL-2 gene expression after in vivo toxin challenge
      target: Massive Polyclonal T Cell Activation
      direction: INCREASED
      interpretation: >-
        Read as the T cell activation output of superantigen challenge; abolished when
        the T cell receptor binding site is mutated.
      evidence:
      - reference: PMID:22069685
        reference_title: "Staphylococcal superantigen (TSST-1) mutant analysis reveals that t cell activation is required for biological effects in the rabbit including the cytokine storm."
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: >-
          T cell activation has been assessed by lymphocyte proliferation and IL-2 gene
          expression after in vivo challenge with TSST-1 and the mutant antigens
        explanation: >-
          States the specific readouts used to measure T cell activation in this model.
    evidence:
    - reference: PMID:22069685
      reference_title: "Staphylococcal superantigen (TSST-1) mutant analysis reveals that t cell activation is required for biological effects in the rabbit including the cytokine storm."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: >-
        Our experimental model of choice is the rabbit because it is comparable to
        humans in its sensitivity to sAg.
      explanation: >-
        Justifies the rabbit as informative for human superantigen biology on the basis
        of comparable superantigen sensitivity.
discussions:
- discussion_id: ivig_mortality_benefit_tss
  kind: CONTROVERSY
  status: OPEN
  prompt: >-
    Does adjunctive intravenous immunoglobulin reduce mortality in streptococcal toxic
    shock syndrome?
  attaches_to:
  - pathophysiology#Superantigen-Mediated MHC Class II and TCR Vbeta Cross-Linking
  rationale: >-
    The mechanistic rationale is strong and specific: pooled donor immunoglobulin should
    neutralize circulating superantigen and so interrupt the MHC class II/TCR bridging
    step this entry models as the initiating molecular event. The clinical evidence does
    not settle the question. A systematic review and meta-analysis restricted to
    clindamycin-treated streptococcal TSS reported mortality falling from 33.7% to 15.7%
    with consistency across one randomized and four non-randomized studies, whereas a
    Japanese nationwide observational study of 481 patients with invasive group A
    streptococcal infection found no effect on in-hospital mortality after adjustment or
    after propensity-score matching. The two are not straightforwardly comparable: the
    positive estimate is conditioned on concurrent clindamycin and confined to
    streptococcal TSS, while the null result covers invasive group A streptococcal
    infection broadly, and its own authors caution against extrapolating to
    streptococcal TSS. Disease rarity makes an adequately powered randomized trial
    difficult. The treatment entry therefore carries both a SUPPORT and a REFUTE
    evidence item rather than a single adjudicated verdict.
  evidence:
  - reference: PMID:37586661
    reference_title: "Effectiveness of intravenous immunoglobulin therapy for invasive group A Streptococcus infection: A Japanese nationwide observational study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: >-
      However, these overall findings should not be extrapolated to streptococcal toxic
      shock syndrome as the effect of IVIG therapy in this condition remains uncertain.
    explanation: >-
      The null-result authors themselves state that the effect in streptococcal TSS
      remains uncertain, which is the open question recorded here.
datasets:
- accession: geo:GSE130125
  title: Delineating the molecular pathways regulated by IFN-gamma and IL-17 in the small
    intestines of humanized mice during staphylococcal superantigen-induced toxic shock
    syndrome
  description: >-
    RNASeq identified several pathways that were differentially expressed/regulated in
    the small intestines that correlated with intestinal failure during toxic shock
    syndrome caused by staphylococcal superantigen in a humanized mouse model
  organism:
    preferred_term: mouse
    term:
      id: NCBITaxon:10090
      label: Mus musculus
  data_type: BULK_RNA_SEQ
  sample_count: 21
  publication: PMID:32676080
  notes: >-
    Identified by GEO DataSets index search for Toxic Shock Syndrome
    (scripts/discover_datasets.py); accession and metadata verified against NCBI
    E-utilities on 2026-08-11. Title, sample count, and organism are GEO's own values.
    Relevance triaged manually: the study is explicitly a staphylococcal
    superantigen-induced TSS model in HLA-humanized mice.
- accession: geo:GSE52474
  title: Late Multiple Organ Surge in Interferon-regulated Target Genes Characterizes
    Staphylococcal Enterotoxin B Lethality
  description: >-
    Bacterial superantigens are virulence factors that cause toxic shock syndrome. Here,
    the genome-wide, temporal response of mice to lethal intranasal staphylococcal
    enterotoxin B (SEB) was investigated in six tissues (PBMC, lung, spleen, kidney,
    heart, Liver).
  organism:
    preferred_term: mouse
    term:
      id: NCBITaxon:10090
      label: Mus musculus
  data_type: MICROARRAY
  sample_count: 154
  publication: PMID:24551153
  notes: >-
    Identified by GEO DataSets index search for Toxic Shock Syndrome
    (scripts/discover_datasets.py); accession and metadata verified against NCBI
    E-utilities on 2026-08-11. Relevance triaged manually: a multi-tissue time course of
    lethal superantigen challenge, matching the multi-organ dysfunction node.
- accession: geo:GSE124756
  title: Comparison of Transcriptional Signatures of Three Staphylococcal Superantigenic
    Toxins in Human Epidermal Melanocytes
  description: >-
    The focus of this study was to determine the distinct and shared mechanisms of
    response to three toxins of the superantigenic family, namely SEA, SEB and TSST-1.
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: MICROARRAY
  sample_count: 19
  publication: PMID:35740423
  notes: >-
    Identified by GEO DataSets index search for Toxic Shock Syndrome
    (scripts/discover_datasets.py); accession and metadata verified against NCBI
    E-utilities on 2026-08-11. Relevance triaged manually: a human-cell comparison of
    the three staphylococcal superantigens named in this entry's toxin-production node.
- accession: geo:GSE15571
  title: Gene Expression Changes Induced by Bacterial Superantigen, Staphylococcal
    Enterotoxin B
  description: >-
    Toxic shock syndrome (TSS) is an acute, serious systemic illness caused by bacterial
    superantigens (BSAg). We characterized the early molecular events underlying TSS
    using our HLA-DR3 transgenic mouse model and studied gene expression profiling using
    DNA microarrays.
  organism:
    preferred_term: mouse
    term:
      id: NCBITaxon:10090
      label: Mus musculus
  data_type: MICROARRAY
  sample_count: 16
  publication: PMID:19336531
  notes: >-
    Identified by GEO DataSets index search for Toxic Shock Syndrome
    (scripts/discover_datasets.py); accession and metadata verified against NCBI
    E-utilities on 2026-08-11. Relevance triaged manually: an HLA-DR3 transgenic mouse
    TSS model, the humanized-MHC approach that overcomes wild-type murine superantigen
    resistance.
notes: >-
  Curated with the claude_code deep research provider. Two corrections were made to the
  provider's report during verification. It proposed HP:0031013 for strawberry tongue;
  that identifier is Ankylosis, and HP:0031042 was substituted after OAK lookup. It also
  reported that no MONDO identifier could be confirmed for TSS; MONDO:0001881 was found
  directly by OAK, with MONDO:0020545 and MONDO:0020544 for the staphylococcal and
  streptococcal subtypes. Every PMID cited by the report and used here was independently
  checked against PubMed and matched its stated topic. Phenotype evidence was repointed
  after review (PR #8321): several findings had initially been supported by a scope
  statement from the PMID:38247655 abstract, which asserts only that the review covers
  clinical presentation and so supports no individual phenotype. Those are now cited to
  enumerating sentences -- the Todd index case series in PMID:38247655 and PMID:32461307,
  the menstrual-TSS series in PMID:38247655, and the STSS case-ascertainment criteria in
  PMID:36456018. The muscular criterion was rewritten: "Severe Myalgia" and "Elevated
  Creatine Kinase" were merged into a single evidence-backed "Myositis" phenotype,
  because no source in the reference set states either myalgia or a creatine kinase
  threshold in TSS, while the STSS criteria name myositis explicitly. The `muscular`
  category remains among the organ systems enumerated in the `definitions` block, but
  that block names the category without stating its content, so severe myalgia and the
  creatine kinase threshold are recorded nowhere in this entry -- a deliberate gap
  rather than an oversight, and a target for a source that states them. No `frequency`
  band is asserted anywhere in this entry. Fever, rash,
  hypotension and desquamation are required criteria of the case definition, so their
  near-universal rate among confirmed cases is an ascertainment artifact rather than a
  measured frequency; per the frequency-evidence guidelines the band is omitted rather
  than justified circularly, and `diagnostic: true` carries the criterion status instead.

📚

References & Deep Research

References

2

PMID:38247655

Toxic Shock Syndrome: A Literature Review.

No top-level findings curated for this source.

PMID:19393958

Gram-positive toxic shock syndromes.

No top-level findings curated for this source.

Deep Research

1

Claude Code ▸

Toxic Shock Syndrome (TSS): Comprehensive Research Report

claude-haiku-4-5-20251001, claude-sonnet-5 45 citations 2026-08-11T01:21:02.907177

Toxic Shock Syndrome (TSS): Comprehensive Research Report

1. Disease Information

Overview

Toxic Shock Syndrome (TSS) is an acute, rapidly progressive, toxin-mediated multisystem illness caused by exotoxin-producing strains of Staphylococcus aureus (staphylococcal TSS) or Streptococcus pyogenes (Group A Streptococcus; streptococcal TSS, STSS), and rarely group C or G streptococci. The defining pathophysiologic feature is bacterial superantigen exotoxin production that triggers massive, non-specific polyclonal T-cell activation and a resulting cytokine storm, producing high fever, diffuse erythematous ("sunburn-like") rash with later desquamation, hypotension/shock, and multi-organ dysfunction (NCBI Bookshelf StatPearls, NBK459345; PMC10812596, "Toxic Shock Syndrome: A Literature Review," PMID:38247655).

"Central to pathogenesis is TSST-1, which bypasses conventional antigen processing by cross-linking MHC class II molecules on antigen-presenting cells with T cell receptors, triggering massive polyclonal T cell activation and a resultant cytokine storm. The ensuing release of interleukins, tumour necrosis factor and other mediators leads to fever, hypotension and multi-organ dysfunction." (PMC10812596)

TSS is historically associated with high-absorbency tampon use in menstruating women (menstrual TSS, mTSS), but non-menstrual TSS (nmTSS) — arising from surgical-site infections, burns, nasal packing, postpartum/puerperal infection, skin/soft-tissue infection, influenza-associated superinfection, and retained foreign bodies (barrier contraceptives, dialysis catheters) — is now more common than menstrual disease in the U.S. (StatPearls NBK459345; CDC MMWR historical surveillance).

Key Identifiers

ICD-10-CM: A48.3 (Toxic shock syndrome)
ICD-11: 1C45 (bacterial TSS); 1C45.0 (streptococcal TSS)
Orphanet: ORPHA:36234 (Bacterial toxic shock syndrome); ORPHA:99918 (Streptococcal toxic-shock syndrome)
MeSH: D017676 (Shock, Septic — parent category); specific MeSH descriptor "Shock, Toxic" (D014017)
MONDO / OMIM: TSS is an acquired infectious-toxin syndrome, not a monogenic Mendelian disease, so it lacks a dedicated OMIM phenotype MIM number in the classical sense; MONDO cross-references the Orphanet/ICD entities above. (No specific MONDO ID was confirmed in available search results — flagged as a gap for curator lookup via the MONDO OLS browser.)

Synonyms / Alternative Names

Staphylococcal toxic shock syndrome; Streptococcal toxic shock syndrome (STSS); Streptococcal toxic shock-like syndrome (TSLS); Tampon disease (historical, non-preferred); Toxic shock-like syndrome.

Evidence Basis

Information is derived predominantly from aggregated disease-level resources: CDC national notifiable-disease surveillance (active, passive, and enhanced surveillance systems since 1980), case-control epidemiologic studies, case series/cohorts from pediatric and adult ICUs, and structured case reports — rather than large-scale EHR data mining, reflecting TSS's rarity and its status as a nationally notifiable condition in the U.S.

2. Etiology

Disease Causal Factors

TSS is fundamentally an infectious/toxin-mediated disease, not genetic — though host genetic factors modulate susceptibility (see below).

Staphylococcal TSS: caused by toxigenic S. aureus strains producing TSST-1 (toxic shock syndrome toxin-1), and less commonly staphylococcal enterotoxins B and C (SEB, SEC), which act as superantigens. Both MSSA and CA-MRSA strains have been implicated.
Streptococcal TSS (STSS): caused by Streptococcus pyogenes (Group A Streptococcus, GAS) producing streptococcal pyrogenic exotoxins (Spe A, SpeB, SpeC) acting as superantigens, often in the context of invasive soft-tissue infection/necrotizing fasciitis. Rarely, group C or G streptococci cause an analogous syndrome.

"M-proteins, especially types 1 and 3, and the streptococcal pyrogenic exotoxin A (speA) play an important role in the pathogenesis of the infection... M protein is an important virulent determinant of GAS; strains lacking M protein are less virulent." (search synthesis, CDC EID 1995 review; PubMed 9331631)

The most common GAS emm genotypes associated with STSS/shock and multiorgan damage are emm1, emm3, emm12, emm28, and emm89, with the hypervirulent M1_UK lineage recently replacing M1_global in some regions (PMC10825083; PMC11705883, Argentina 2023 genomic surveillance). Mutations in the CovRS two-component regulatory system are implicated in the switch to an invasive/toxigenic phenotype.

Risk Factors

Genetic risk factors: - HLA class II alleles strongly determine the magnitude of the anti-TSST-1 antibody response: HLA-DRB1*03:01 and HLA-DQB1*02:01 are positively associated, while HLA-DRB1*01:01 and HLA-DQB1*05:01 are negatively associated with anti-TSST-1 antibody titers (PMC10507260). Women who fail to seroconvert after TSST-1 exposure may carry HLA class II genotypes associated with a genetically higher intrinsic risk of TSS. - Absence or low titer of neutralizing anti-TSST-1 antibody is considered a core host-susceptibility factor — classic work by Bonventre/Parsonnet-era investigators found antibody levels in TSS cases were significantly lower than in matched controls without a TSS history (search synthesis; PMID:6491377; PMID:17340193).

Environmental / behavioral risk factors: - Use of high-absorbency tampons (historically superabsorbent polyacrylate-containing tampons, withdrawn from market in 1980); tampon oxygen content appears more strongly associated with TSS risk than absorbency or chemical composition per se (ScienceDirect 089543569090105X). - Nasal packing after nasal/sinus surgery — "Nasal packing was used in all patients with TSS and in 98% of all patients" in one post-nasal-surgery case series (PMID:3942641). - Surgical wound infection, postpartum/puerperal infection, burns, retained foreign bodies (diaphragms, cervical caps, dialysis catheters), skin/soft-tissue infection or varicella superinfection, recent influenza infection, and immunocompromised states. - 15–33% of TSS cases occur without an identifiable predisposing risk factor (StatPearls NBK459345).

Protective Factors

Circulating neutralizing antibody to TSST-1 (or to the relevant streptococcal exotoxins) is the principal known protective factor; most adults acquire protective anti-TSST-1 antibody through subclinical colonization/exposure over time.
Removal of superabsorbent tampon formulations from the U.S. market (early 1980s) was followed by a marked decline in menstrual TSS incidence (from 6–12/100,000 in 1980 to ~1/100,000 by 1986) (CDC MMWR historical surveillance).
Beta-lactamase-resistant antistaphylococcal antibiotic therapy after a first episode reduces recurrence risk.

Gene-Environment Interactions

The clearest documented gene-environment interaction is between HLA class II genotype and toxin exposure: "Both toxin exposure and HLA alleles affect the human antibody response to TSST-1" (PMC10507260) — i.e., an individual's genetically determined capacity to mount a neutralizing humoral response, combined with the degree/duration of environmental toxin exposure (e.g., prolonged high-absorbency tampon use enabling S. aureus toxin elaboration in a low-oxygen vaginal microenvironment), jointly determines whether clinical TSS develops after colonization.

3. Phenotypes

TSS phenotypes span symptoms, physical signs, and laboratory abnormalities, with an abrupt onset and rapid (24–48 hour) progression.

Symptoms / Early Prodrome

Sudden-onset high fever, chills, headache, sore throat, vomiting, watery diarrhea, and severe myalgia, typically preceding hypotension and rash by 24–48 hours (search synthesis; HPO suggestion: HP:0001945 Fever; HP:0002018 Nausea and vomiting; HP:0002014 Diarrhea; HP:0003326 Myalgia).

Clinical Signs / Physical Manifestations

Diffuse macular erythroderma ("sunburn-like rash") — HP:0000988 Skin rash / a more specific erythroderma term.
Desquamation, classically palms/soles, occurring 1–2 weeks after rash onset, with full-thickness peeling — HP:0025044 (Desquamation) if available in HPO, or closest matching term.
Strawberry tongue and mucosal hyperemia (oropharyngeal, conjunctival, vaginal) — HP:0031013 (Strawberry tongue).
Hypotension / shock — HP:0002615 (Hypotension) / HP:0001744-adjacent shock terminology.
Peripheral edema, non-pitting edema of hands/feet.
Altered mental status/disorientation without focal neurologic deficits — HP:0007018 (Attention deficit) is not ideal; better: HP:0000733 (Agitation) or generically HP:0002360 (Sleep disturbance) — most fitting is a general "confusion"/"altered consciousness" term (HP:0031466 Confusion or HP:0002015-related encephalopathy term).
Soft-tissue necrosis / necrotizing fasciitis in STSS — HP:0032658 (Skin ulcer)-adjacent or necrosis-specific term.
Conjunctival injection/hyperemia — HP:0000585 (Conjunctivitis) or HP:0000998-adjacent.

Laboratory Abnormalities

Elevated creatine phosphokinase (≥2× ULN) — reflecting myositis/muscle injury.
Elevated BUN/creatinine (≥2× ULN) or sterile pyuria (≥5 WBC/hpf).
Elevated bilirubin/transaminases (≥2× ULN) — hepatic involvement.
Thrombocytopenia (platelets ≤100,000/mm³), often DIC-pattern coagulopathy with prolonged clotting times, low fibrinogen, elevated fibrin degradation products.
Leukocytosis or leukopenia with bandemia/left shift.
Hypocalcemia — described as "prominent throughout the disease" in StatPearls (NBK459345).
Negative blood/CSF cultures for other pathogens (part of the case-definition exclusionary lab criteria); blood cultures may be positive for S. aureus in staphylococcal TSS (unlike STSS, where blood cultures are frequently positive for GAS).

Phenotype Characteristics

Age of onset: any age; menstrual TSS peaks in females aged 15–19 (incidence 1.52/100,000); pediatric STSS is well described; elderly patients with STSS have notably worse prognosis.
Severity: variable, ranging from moderate illness to fulminant multi-organ failure and death within 24–96 hours, especially in STSS.
Progression: acute and rapid — "signs of soft tissue infection... can lead to necrotizing fasciitis... kills 30–60% of patients in 72–96 hours" (search synthesis on STSS/necrotizing fasciitis).
Frequency of organ involvement: by CDC case definition, ≥3 organ systems must be involved for a probable/confirmed staphylococcal TSS diagnosis (GI, muscular, mucous membrane, renal, hepatic, hematologic, CNS).

Quality of Life Impact

Long-term survivor data (see Outcome/Prognosis, §11) document persistent sequelae — cognitive/memory complaints, new-onset allergies, Raynaud phenomenon, dermatitis, and organ-specific hospitalization risk — that can meaningfully affect post-illness quality of life, though most patients recover without major long-term handicap if treated early (toxicshock.com "After TSS"; PMC via ScienceDirect Long-term outcomes cohort study, J Infect 2024).

4. Genetic/Molecular Information

TSS is not caused by a germline pathogenic variant in a human disease gene — there is no "causal gene" in the Mendelian sense. The molecular basis instead resides in bacterial virulence genes:

Staphylococcal TSST-1: encoded by the tst gene, carried on a mobile pathogenicity island (SaPI) in a subset of S. aureus strains; also relevant are sea/sec enterotoxin genes (staphylococcal enterotoxin B/C) as alternative superantigens.
Streptococcal exotoxins: speA, speB, speC genes in S. pyogenes, with M-protein (emm gene) serotype and covRS regulatory mutations modulating invasiveness/toxin expression.

Host Genetic Modifiers

HLA-DRB1/DQB1 class II haplotypes (see §2) modulate the strength and quality of the anti-TSST-1 antibody response and thus host susceptibility — this is the best-characterized human genetic modifier locus for TSS. (HGNC: HLA-DRB1, HLA-DQB1)
No pathogenic germline variant classification (ACMG/AMP), allele frequency in gnomAD, or somatic/germline distinction applies in the conventional sense, since TSS pathophysiology is toxin-driven rather than variant-driven.

Epigenetic / Chromosomal Information

No disease-specific epigenetic signature or chromosomal abnormality has been established for TSS; this section is not applicable in the classical Mendelian-disease sense. (Bacterial mobile genetic elements — SaPIs carrying tst — are the closest analogous "genomic structural feature," but these are bacterial, not human, genomic elements.)

5. Environmental Information

Environmental Factors

Superabsorbent tampon materials (historically carboxymethylcellulose/polyacrylate rayon blends) that increase vaginal oxygen tension and S. aureus toxin elaboration.
Nasal packing materials/tampons used post-surgically.
Retained barrier contraceptive devices (diaphragms, cervical caps, contraceptive sponges).
Surgical wound environments, burns, and postpartum uterine environment as niches for toxigenic organism proliferation.

Lifestyle Factors

Duration of tampon use per cycle and continuous (rather than intermittent) tampon wear.
Not using tampons does not eliminate risk — cases have been documented in women colonized by TSST-1-producing S. aureus who never used tampons, including recurrent TSS despite abstaining from tampon use post-first episode (Lancet Infect Dis systematic review, PMID:31151811).

Infectious Agents

Staphylococcus aureus (toxigenic, TSST-1/SEB/SEC-producing strains, MSSA and MRSA) — NCBI Taxonomy: NCBITaxon:1280.
Streptococcus pyogenes (Group A Streptococcus) — NCBITaxon:1314; rarely group C/G streptococci.
Antecedent viral infection (e.g., influenza, varicella) creating a portal for secondary toxigenic bacterial superinfection is a recognized non-menstrual TSS risk context.

6. Mechanism / Pathophysiology

Causal Chain (Upstream → Downstream)

Colonization/infection with a toxigenic strain (vaginal S. aureus colonization in mTSS; wound/soft-tissue GAS infection in STSS) in a host lacking protective neutralizing antibody.
Superantigen exotoxin production (TSST-1, SEB/SEC for staph; SpeA/B/C for strep) in a permissive microenvironment (e.g., elevated vaginal O₂ tension from tampon use; devitalized/necrotic tissue in soft-tissue infection).
Non-conventional MHC-II/TCR cross-linking: the superantigen binds directly to MHC class II molecules on antigen-presenting cells outside the conventional peptide-binding groove, and simultaneously to the variable β (Vβ) chain of the T-cell receptor, bypassing normal antigen-specific presentation.

"TSST-1... binds to the MHC class II outside the antigen presentation site and the variable beta (Vβ) chain of the T-cell receptor... leading to nonspecific, polyclonal lymphocyte activation of 5-30% of the total population of T cells." (search synthesis on superantigen mechanism; PMC6468478, "Staphylococcal Superantigens: Pyrogenic Toxins Induce Toxic Shock")

Massive polyclonal T-cell activation and cytokine storm: activated T cells and macrophages release TNF-α, TNF-β, IL-1β, IL-2, IL-6, and IFN-γ, plus chemokines such as macrophage chemoattractant protein-1 (MCP-1). Downstream signaling includes MAPK cascades, NF-κB activation, and PI3K/Akt/mTOR pathway engagement.
Systemic inflammatory/vascular effects: cytokine-mediated capillary leak, vasodilation, endothelial activation/dysfunction (demonstrated directly on human aortic endothelial cells, PMID:29229737), and disseminated microvascular injury.
Clinical manifestation: fever, diffuse erythroderma, profound hypotension/distributive shock, and multi-organ dysfunction (renal, hepatic, hematologic/coagulopathy, muscular, CNS), with desquamation as a late cutaneous sequela of the acute inflammatory insult.
In STSS, a parallel/overlapping mechanism involves M-protein-mediated antiphagocytic virulence, enabling invasive soft-tissue infection and necrotizing fasciitis, compounding shock with local tissue destruction and a markedly higher case-fatality rate than staphylococcal TSS.

Cellular Processes

T-lymphocyte hyperactivation and clonal (Vβ-restricted) expansion (e.g., TRBV12-3/12-4+ memory T cells specifically activated by SpeC and TSST-1; PMC9854414).
Macrophage/monocyte activation and inflammatory cytokine secretion.
Vaginal/epithelial cell activation — TSST-1 interacts with CD40 on vaginal epithelial cells to stimulate chemokine production that facilitates local T-cell/macrophage activation (search synthesis; PMC6426597).
Suppression of epithelial autophagy by TSST-1 (PMC4234639).
Endothelial dysfunction and vascular leak.
Neutrophil/complement-mediated tissue injury in soft-tissue necrosis (STSS).

Suggested Ontology Terms

GO:0002347 (response to bacterial pathogen-associated pattern) / GO:0035723 (interleukin-6-mediated signaling pathway) / GO:0033209 (tumor necrosis factor-mediated signaling pathway) / GO:0043123 (positive regulation of I-kappaB kinase/NF-kappaB signaling) for the cytokine/NF-κB cascade.
GO:0002827 (positive regulation of T-helper 1 type immune response) / GO:0042104 (positive regulation of activated T cell proliferation) for polyclonal T-cell activation.
CL:0000084 (T cell), CL:0000235 (macrophage), CL:0000738 (leukocyte), CL:0000115 (endothelial cell), CL:0002144 (capillary endothelial cell) for cell types involved.
CHEBI: TSST-1 and streptococcal pyrogenic exotoxins are proteins rather than small molecules and are better represented as UniProt/GO molecular entities than CHEBI terms.

7. Anatomical Structures Affected

Organ Level

Primary: skin/integument (rash, desquamation), cardiovascular system (hypotension/distributive shock), and the primary infectious site (vaginal mucosa in mTSS; skin/soft tissue, surgical wound, or uterus in nmTSS/STSS).
Secondary/multisystem: kidneys (acute kidney injury, often an early sign preceding hypotension), liver (transaminitis, hyperbilirubinemia), hematologic system (thrombocytopenia, DIC), skeletal muscle (myositis, elevated CPK), gastrointestinal tract (vomiting, diarrhea), and central nervous system (encephalopathy/confusion).
Body systems involved: integumentary, cardiovascular, renal, hepatic, hematologic/immune, musculoskeletal, gastrointestinal, and (in severe STSS) the deep soft-tissue/fascial plane.

Suggested UBERON terms: UBERON:0002097 (skin epidermis), UBERON:0000178 (blood), UBERON:0002113 (kidney), UBERON:0002107 (liver), UBERON:0001134 (skeletal muscle tissue), UBERON:0000948 (heart)/UBERON:0001981 (blood vessel) for the vasculature, UBERON:0000996 (vagina) for the mTSS primary site, UBERON:0002097-adjacent fascia term for STSS necrotizing fasciitis.

Tissue and Cell Level

Vaginal squamous epithelium (site of TSST-1 elaboration and CD40-mediated chemokine induction in mTSS).
Vascular endothelium (aortic/capillary endothelial dysfunction).
Deep fascia and subcutaneous soft tissue (necrotizing fasciitis in STSS).
Peripheral blood T lymphocytes and monocytes/macrophages as the principal toxin-responsive cell populations.

Subcellular Level

MHC class II molecules at the plasma membrane of antigen-presenting cells (GO:0042613, MHC class II protein complex) — the direct molecular docking site for superantigen.
Signal transduction machinery: NF-κB pathway components (nuclear translocation), MAPK cascade proteins, PI3K/Akt/mTOR pathway components — largely cytoplasmic/nuclear.

Localization

Bilateral/systemic — TSS is a systemic toxin-mediated disease without lateralization; cutaneous rash is typically diffuse and symmetric.

8. Temporal Development

Onset

Age: can occur at any age (neonatal through geriatric); menstrual TSS is essentially confined to menstruating individuals (peak 15–19 years); pediatric non-menstrual TSS and STSS are well documented (PMID:29601458, "Epidemiology and Clinical Relevance of Toxic Shock Syndrome in US Children").
Onset pattern: acute — sudden onset of fever/flu-like prodrome, with hypotension, rash, and multi-organ involvement developing within 24–48 hours.

Progression

Disease course: rapid and fulminant, particularly STSS with necrotizing fasciitis, which "kills 30–60% of patients in 72–96 hours" absent aggressive intervention.
Progression rate: STSS-associated mortality has been reported to exceed 25% within the first 24 hours in some cohorts.
Disease duration: acute, self-limited illness with appropriate treatment (source control + antibiotics + supportive care); desquamation phase resolves over 1–2+ weeks after the acute illness.
Recurrence is well documented in menstrual TSS (up to ~14/44 cases in early cohorts having ≥1 recurrence), particularly without antistaphylococcal antibiotic therapy or continued tampon use; recurrence can occur even after tampon cessation in colonized women.

Patterns

Remission: typically treatment-induced (source control + antibiotics + supportive/ICU care) rather than spontaneous, though the disease is not chronic — surviving patients generally achieve full clinical resolution of the acute episode.
Critical periods: early recognition and rapid initiation of source control (tampon/foreign body removal, wound debridement) plus toxin-suppressing antibiotic therapy (clindamycin) within the first hours of presentation are repeatedly emphasized as the key modifiable window affecting mortality.

9. Inheritance and Population

Epidemiology

Overall U.S. incidence: ~0.8–3.4 per 100,000 (StatPearls NBK459345), though estimates vary substantially by era and surveillance method.
Menstrual TSS incidence: historically 6–12/100,000 women aged 12–49 (1980), declining to ~1/100,000 women 15–44 by 1986 following superabsorbent tampon withdrawal; current estimates ~0.5–1.0/100,000; peak incidence 1.52/100,000 in women 15–19.
Non-menstrual TSS: now exceeds menstrual TSS incidence; by 1986, menstrual vs. non-menstrual rates were roughly 1 vs. 0.3/100,000, with the gap subsequently reversing.
Streptococcal TSS (STSS): annual incidence ~1/300,000–1/1,000,000 per Orphanet; alternative estimates of 2–4 cases per 100,000 per year have also been reported; STSS accounts for ~4% of invasive GAS disease overall.
Worldwide bacterial TSS prevalence: estimated at ~1/30,000 (Orphanet).

Inheritance Pattern

TSS is not a Mendelian genetic disease — there is no inheritance pattern (AD/AR/X-linked/mitochondrial) in the classical sense. Susceptibility is polygenic/immunogenetic, chiefly modulated by HLA class II genotype, which affects antibody-mediated protection but does not itself "cause" disease. Penetrance, expressivity, anticipation, germline mosaicism, and carrier-frequency concepts are not applicable.

Population Demographics

Sex ratio: menstrual TSS is essentially female-only by definition; across all TSS (menstrual + non-menstrual), approximately 85% of cases occur in females and 15% in males (search synthesis).
Race/ethnicity: historical U.S. surveillance found higher menstrual TSS incidence in white women than non-white women (1.21/100,000 vs. 0.34/100,000).
Age distribution: bimodal relevance — menstrual TSS peaks in adolescent/young adult females (15–19 years); non-menstrual and streptococcal TSS occur across the age spectrum, with STSS notably more severe/lethal in elderly patients.
Geographic distribution: occurs worldwide; STSS/invasive GAS disease shows regional variation in dominant emm genotypes (e.g., emm1/M1_UK lineage replacement documented in parts of Europe; emm1-global and hypervirulent emm1 lineages highlighted in South American surveillance).
Seasonality: StatPearls notes TSS occurs year-round but with somewhat higher winter prevalence, and increased frequency reported in developing nations.

10. Diagnostics

Clinical Case Definition (CDC, 2011 — Staphylococcal TSS)

All five clinical criteria are required for a confirmed case (or death before desquamation occurs); four of five plus laboratory criteria define a probable case:

Fever: temperature ≥102.0°F (≥38.9°C)
Rash: diffuse macular erythroderma
Desquamation: 1–2 weeks after rash onset (palms/soles classically)
Hypotension: systolic BP ≤90 mmHg (adults) or <5th percentile for age (children <16)
Multisystem involvement (≥3 of the following):
Gastrointestinal (vomiting or diarrhea at onset)
Muscular (severe myalgia or CPK ≥2× ULN)
Mucous membrane (vaginal, oropharyngeal, or conjunctival hyperemia)
Renal (BUN/creatinine ≥2× ULN, or pyuria ≥5 WBC/hpf without UTI)
Hepatic (bilirubin or transaminases ≥2× ULN)
Hematologic (platelets <100,000/mm³)
CNS (disorientation/altered consciousness without focal signs, in the absence of fever/hypotension)

Laboratory criteria: negative blood/CSF cultures (blood culture may be positive for S. aureus) and negative serologies for Rocky Mountain spotted fever, leptospirosis, and measles. (Source: CDC National Notifiable Diseases case-definition portal, ndc.services.cdc.gov)

Streptococcal TSS clinical criteria are analogous but require hypotension plus ≥2 of: renal impairment, coagulopathy, hepatic involvement, ARDS, generalized erythematous macular rash, and soft-tissue necrosis/necrotizing fasciitis, together with isolation of S. pyogenes (from a sterile site for a confirmed case; non-sterile site for probable).

Laboratory Tests

No single specific diagnostic test exists; diagnosis is clinical/syndromic per case-definition criteria.
CBC (leukocytosis or leukopenia with bandemia, thrombocytopenia, anemia), comprehensive metabolic panel (renal/hepatic function), creatine phosphokinase, coagulation studies (PT/PTT, fibrinogen, D-dimer for DIC), blood/wound/vaginal cultures.
Acute kidney injury is frequently the earliest organ-injury sign, often preceding hypotension.
Hypocalcemia is a notable and prominent laboratory abnormality throughout the illness course.

Genetic Testing

Not applicable/not indicated for diagnosis — TSS is not diagnosed via genetic testing (no WGS/WES/gene panel/CMA/karyotype role), reflecting its infectious/toxin-mediated (not germline) etiology. HLA typing has research relevance for susceptibility studies but is not part of routine clinical diagnostics.

Imaging / Other

CT/MRI may be used adjunctively to evaluate for necrotizing fasciitis extent or abscess/retained foreign body in non-menstrual TSS, but imaging is not part of the core case definition.

Differential Diagnosis

Scarlet fever, Kawasaki disease, meningococcemia, toxic epidermal necrolysis/Stevens-Johnson syndrome, necrotizing fasciitis (as a co-occurring/overlapping entity in STSS), drug eruptions, erythema multiforme, and — in pediatric populations — multisystem inflammatory syndrome in children (MIS-C) (PMC10056689, comparative pediatric study of MIS-C, Kawasaki disease, and TSS).

Screening

No population-based screening program exists; risk-reduction counseling (tampon absorbency/duration, foreign-body management) functions as informal primary prevention rather than formal screening.

11. Outcome/Prognosis

Survival and Mortality

Staphylococcal (non-streptococcal) TSS: case-fatality generally <3%, with some modern series citing an overall range of 1.8–12%.
Streptococcal TSS (STSS): substantially higher mortality — commonly cited as 30–60%, with some sources reporting up to 80% in adults versus 5–8% in children; a Japanese nationwide investigation found an overall mortality rate of 45%; STSS-associated mortality can exceed 25% within the first 24 hours.
When STSS is complicated by necrotizing fasciitis, mortality of 30–60% within 72–96 hours has been reported.
STSS accounts for a small fraction (~4%) of invasive GAS disease overall but disproportionately drives GAS-associated mortality (~38% case-fatality cited for STSS specifically in some series).
Delayed diagnosis/treatment is consistently identified as a major driver of increased mortality across both staphylococcal and streptococcal TSS.

Morbidity and Long-Term Function

Reported long-term sequelae in survivors include: late-onset rash, compromised renal function, cyanotic extremities, prolonged neuromuscular abnormalities, dermatitis, new-onset allergies, and Raynaud phenomenon.
Neurocognitive sequelae are notable: EEG abnormalities, difficulty concentrating, headache, and memory lapses are described post-recovery, with one study finding survivors had reduced left hippocampal volume compared to healthy controls.
A recent matched cohort study (J Infect 2024) found TSS "strongly associated with the risk of renal, cardiovascular, and hepatic hospitalization" in the post-acute period.
Severe complications include digit/limb gangrene (potentially requiring amputation) and renal failure, though these are described as rare with early, aggressive treatment.
Overall, "most patients recover completely and without any significant long-term handicap" when treated promptly.

Prognostic Factors

Organism (streptococcal >> staphylococcal severity), timeliness of diagnosis/source control, presence/extent of necrotizing soft-tissue infection, patient age (elderly patients with STSS fare markedly worse), and emm genotype (emm1/emm3/emm89 associated with more severe invasive disease).

12. Treatment

Pharmacotherapy

Empiric broad-spectrum antibiotics pending culture identification, typically including vancomycin or linezolid for MRSA coverage.
Clindamycin is added specifically as an antitoxin/protein-synthesis-inhibiting adjunct — it suppresses toxin (TSST-1/streptococcal exotoxin) and cytokine production independent of its bactericidal action; "studies demonstrate improved outcomes when clindamycin is added" (StatPearls NBK459345). IDSA recommends penicillin + clindamycin combination therapy for confirmed streptococcal TSS.
Once organism/susceptibility is confirmed: penicillin for Group A Streptococcus; clindamycin plus an antistaphylococcal penicillin (nafcillin/oxacillin/flucloxacillin) for MSSA.
Typical antibiotic duration: 7–14 days.
NCIT term: NCIT:C15632 (Chemotherapy) is not appropriate; more fitting is NCIT:C15986 (Pharmacotherapy), with therapeutic_agent bindings to CHEBI (e.g., CHEBI for clindamycin, vancomycin, penicillin, linezolid).

Advanced/Adjunctive Therapeutics

Intravenous immunoglobulin (IVIG): proposed mechanism is direct neutralization of circulating superantigen. Evidence is mixed:
A systematic review/meta-analysis of clindamycin-treated STSS patients found mortality fell from 33.7% to 15.7% with IVIG "with remarkable consistency across the single randomized and four nonrandomized studies" (PMC6186853; Clin Infect Dis, PMID referenced in search).
However, a more recent large observational Japanese nationwide study found no significant survival benefit of IVIG after adjustment for confounders, and the single multicenter RCT (Darenberg et al.) was terminated early due to slow recruitment.
Typical proposed dosing: high-dose IVIG, ~2 g/kg, though it remains without definitive RCT-level mortality benefit and guideline recommendations vary.
Corticosteroids: not recommended — no demonstrated mortality benefit.

Surgical/Interventional

Immediate removal of the inciting foreign body (tampon, nasal packing, retained barrier contraceptive/surgical material) is a first-line, urgent intervention.
Emergent surgical debridement/source control for infected/necrotic soft tissue, particularly critical in STSS with necrotizing fasciitis — described as "critical to outcomes."
NCIT term: NCIT:C15329 (Surgical Procedure) / NCIT:C154430 (debridement-related term).

Supportive Care

Aggressive IV crystalloid fluid resuscitation for hypotension.
Vasopressors (norepinephrine preferred) for fluid-refractory shock.
Electrolyte repletion, notably for hypocalcemia.
ICU admission mandatory for all patients; severe cutaneous/desquamating cases may require burn-unit-level care.
NCIT term: NCIT:C15747 (Supportive Care).

Experimental / Preventive Immunotherapy

rTSST-1v (recombinant detoxified TSST-1 variant) vaccine — Phase 1 (PMID:27296693, Lancet Infect Dis 2016) and Phase 2 trials (NCT02814708; PMC10808908, eClinicalMedicine) demonstrate the vaccine is safe, well-tolerated, and highly immunogenic: "Seroconversion occurred in >81% of subjects within 3 months of the first immunisation, sustained until 18 months after the third immunisation in over 70% of subjects." This represents a first-in-class active immunoprophylaxis approach targeting the core superantigen mechanism.
Passive TSST-1-neutralizing monoclonal/single-chain antibody approaches have shown protective efficacy in animal models even when administered late in toxin exposure (PMC4073126; PMC9617332).

Treatment Algorithm Summary

Recognize (case-definition criteria) → remove foreign body/source control → empiric broad-spectrum antibiotics (vancomycin/linezolid + clindamycin) → narrow per culture/organism → aggressive fluid resuscitation ± vasopressors → consider IVIG in refractory/severe STSS → ICU-level supportive care → surgical debridement if soft-tissue necrosis.

13. Prevention

Primary Prevention

Avoidance of superabsorbent tampon formulations (regulatory withdrawal of the highest-absorbency products was a landmark U.S. public-health primary-prevention action in the early 1980s, associated with a large decline in menstrual TSS incidence).
Guidance on tampon use duration/frequency and alternating with pads to reduce continuous high-absorbency exposure.
Careful surgical technique and judicious nasal-packing use/duration following nasal/sinus surgery.
Immunization: no licensed vaccine yet exists, but the rTSST-1v candidate vaccine (Phase 2 completed) represents an active primary-prevention strategy in development, specifically for individuals at recognized risk (e.g., prior TSS survivors, given documented recurrence risk).

Secondary Prevention / Early Detection

Clinical vigilance and rapid application of case-definition criteria in any patient with fever + rash + hypotension, particularly post-surgical, postpartum, or menstruating patients, to enable early source control and antibiotic initiation — repeatedly identified as the single greatest modifiable determinant of survival.
Recommendation for beta-lactamase-resistant antistaphylococcal antibiotic therapy after a first TSS episode to reduce recurrence.

Tertiary Prevention

Post-TSS antistaphylococcal therapy and discontinuation of causative tampon/device use to prevent recurrent episodes, recognizing that recurrence can still occur even after risk-factor removal in colonized individuals.

Public Health / Chemoprophylaxis

The CDC does not recommend routine screening or chemoprophylaxis for household contacts of streptococcal TSS cases; however, providers "may choose to offer chemoprophylaxis to household members aged ≥65 years or those at increased risk," with a suggested regimen of 7–10 days of oral cephalexin (StatPearls NBK459345).
Standard/contact/droplet precautions are recommended for the first 24 hours of effective antibiotic therapy in hospitalized STSS patients.

Counseling

No formal genetic counseling role exists given the non-Mendelian, infectious nature of TSS; counseling is limited to behavioral/device-use risk-reduction education, particularly for TSS survivors regarding recurrence risk.

14. Other Species / Natural Disease

Taxonomy

TSS-like disease is described in domestic dogs (Canis lupus familiaris, NCBITaxon:9615), driven by superantigen-producing Staphylococcus and Streptococcus species.

Natural Disease in Animals

Canine Streptococcal Toxic Shock Syndrome (CSTSS): primarily caused by Streptococcus canis, described as "a serious often fatal disease syndrome seen in dogs" (Veterinary World review, veterinaryworld.org).
Case reports document mixed infections, e.g., S. aureus, Streptococcus halichoeri, and Dermatophilus spp. co-infection producing a toxic shock-like syndrome in a dog (Vet Sci 2025, doi:10.3390/vetsci12080764; PMC12390649).
Clinical presentation parallels the human disease: superantigen-driven massive TNF-α and inflammatory cytokine release, high fever, hypotension, hemoconcentration, thrombosis, and neutrophil/endothelial activation leading to multi-organ failure.
No OMIA (Online Mendelian Inheritance in Animals) entry was identified for TSS, consistent with its non-heritable, infectious basis — this is expected given TSS is toxin/infection-driven rather than a Mendelian trait, and is flagged as an appropriate "not applicable" rather than a knowledge gap.

Comparative Biology

The rabbit is considered the classic experimental model of choice for human TSS specifically because of its comparable sensitivity to staphylococcal/streptococcal superantigens (see Model Organisms, §15) — this cross-species conservation of superantigen sensitivity underscores that the core MHC-II/TCR superantigen mechanism is broadly conserved across mammals, with canine natural disease representing a spontaneous, naturally occurring parallel to the human syndrome.

Zoonotic Considerations

TSS itself is not classically zoonotic (human and canine cases arise from largely host-adapted or opportunistic staphylococcal/streptococcal strains rather than direct animal-to-human transmission), though S. canis is a recognized opportunistic pathogen that can rarely cause human infection.

15. Model Organisms

Rabbit Model (Primary Model)

The rabbit is explicitly identified as "the experimental model of choice because it is comparable to humans in its sensitivity to superantigens" (search synthesis; PMC3153295, PMID:22069685). - Intravaginal TSST-1 administration in rabbits produces 100% lethality in unprotected controls, closely modeling menstrual TSS. - Multiple-dose lethal-challenge protocols (repeated dosing over 5 days) are used to model sustained toxin exposure; TSST-1-neutralizing antibody treatment is fully protective in this model, including when administered late in the course of exposure (PMC4073126) — directly informing the rationale for passive/active immunotherapy development. - A chronic-exposure rabbit model further demonstrated that sustained low-level TSST-1 exposure accelerates atherosclerosis progression (PMC6933490), illustrating a vascular/endothelial dimension of chronic superantigen exposure beyond acute shock. - TSST-1 mutant analysis in rabbits established that T-cell activation is mechanistically required for the biological effects of the toxin, including the cytokine storm itself (PMC3153295).

Mouse Models

Wild-type mice are relatively resistant to staphylococcal/streptococcal superantigens due to poor toxin-MHC class II binding affinity — a significant translational limitation.
HLA class II-transgenic mice (e.g., HLA-DQ8 transgenic) overcome this: "Transgenic expression of human HLA class II can render mice superantigen sensitive and allows investigation of superantigen-associated inflammation without the need for sensitization." Spleen cells from HLA-DQ8 transgenic mice show markedly greater TSST-1 sensitivity than wild-type C57BL/6 cells.
A transgenic mouse model of staphylococcal soft-tissue infection was used to evaluate TSST-1 production in vivo and assess antibiotic impact — early clindamycin treatment altered TSST-1 production in soft tissue and immune organs, directly modeling the toxin-suppression rationale for clindamycin adjunctive therapy in human TSS (PMC6796978, mSphere, "Toxic Shock Syndrome Toxin 1 Evaluation and Antibiotic Impact in a Transgenic Model of Staphylococcal Soft Tissue Infection").

Model Characteristics: Fidelity and Limitations

Recapitulation: both rabbit and HLA-transgenic mouse models successfully reproduce the core superantigen-driven cytokine storm and lethality; the rabbit model in particular captures the acute lethal shock phenotype with high fidelity.
Limitations: standard (non-transgenic) mouse strains fail to recapitulate human-relevant superantigen sensitivity because murine MHC class II binds staphylococcal/streptococcal superantigens poorly — this is a well-recognized species-specific translational gap, addressed only by HLA-humanized transgenic approaches. Rabbit models, while pharmacodynamically closer to human superantigen sensitivity, do not fully capture the human menstrual/vaginal microbiome context in which TSST-1 is naturally elaborated.

Applications

Rabbit and HLA-transgenic mouse models have been used to: (1) establish the causal, T-cell-activation-dependent mechanism of superantigen-induced cytokine storm and lethality; (2) test neutralizing antibody therapeutics (fully protective even late in exposure); (3) evaluate the rTSST-1v vaccine candidate's immunogenicity prior to human trials; and (4) evaluate antibiotic (clindamycin) impact on in vivo toxin production, directly supporting current clinical antitoxin treatment strategy.

Resources

No dedicated TSS-specific model-organism database exists; relevant models are documented in the primary immunology/infectious-disease literature cited above rather than centralized repositories like MGI/IMPC (reflecting that these are typically custom-generated transgenic/challenge models rather than heritable knockout lines cataloged for a Mendelian phenotype).

Summary of Suggested Ontology Term Bindings for KB Curation

Category	Suggested Term(s)
Disease identifiers	ICD-10-CM A48.3; ICD-11 1C45 / 1C45.0; ORPHA:36234 (bacterial TSS); ORPHA:99918 (streptococcal TSS); MONDO term to be confirmed via OLS lookup
Causal organisms	NCBITaxon:1280 (Staphylococcus aureus); NCBITaxon:1314 (Streptococcus pyogenes)
Causal gene (bacterial virulence)	tst (TSST-1), sea/sec (staph enterotoxins), speA/speB/speC (strep exotoxins) — bacterial, not HGNC-mapped
Host modifier genes	HLA-DRB1, HLA-DQB1 (HGNC)
Key phenotypes (HP)	Fever HP:0001945; Hypotension HP:0002615; Strawberry tongue HP:0031013; Myalgia HP:0003326; Diarrhea HP:0002014; Thrombocytopenia HP:0001873
Molecular mechanism (GO)	MHC class II protein complex GO:0042613; TNF-mediated signaling GO:0033209; positive regulation of T cell proliferation GO:0042129/GO:0042104
Cell types (CL)	CL:0000084 T cell; CL:0000235 macrophage; CL:0000115 endothelial cell
Anatomy (UBERON)	UBERON:0002097 skin; UBERON:0000996 vagina; UBERON:0002113 kidney; UBERON:0002107 liver
Treatments (NCIT)	NCIT:C15986 Pharmacotherapy (clindamycin, vancomycin, penicillin — CHEBI-bound `therapeutic_agent`); NCIT:C15329 Surgical Procedure; NCIT:C15747 Supportive Care
Model organisms	Rabbit (Oryctolagus cuniculus); HLA-DQ8-transgenic mouse

Key knowledge gaps flagged for curation: no confirmed dedicated MONDO ID was retrieved in this search pass (should be verified directly against the MONDO OLS browser); IVIG mortality benefit remains genuinely contested in the primary literature (meta-analytic pooled benefit vs. large adjusted observational null-result) and should be curated as a HUMAN_MODEL_MISMATCH/conflicting-evidence discussion rather than a settled treatment-efficacy claim; no OMIA entry exists for the canine analog, consistent with the non-heritable, infectious nature of the disease.

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Toxic Shock Syndrome (TSS): Comprehensive Research Report

1. Disease Information

Overview

Key Identifiers

Synonyms / Alternative Names

Evidence Basis

2. Etiology

Disease Causal Factors

Risk Factors

Protective Factors

Gene-Environment Interactions

3. Phenotypes

Symptoms / Early Prodrome

Clinical Signs / Physical Manifestations

Laboratory Abnormalities

Phenotype Characteristics

Quality of Life Impact

4. Genetic/Molecular Information

Host Genetic Modifiers

Epigenetic / Chromosomal Information

5. Environmental Information

Environmental Factors

Lifestyle Factors

Infectious Agents

6. Mechanism / Pathophysiology

Causal Chain (Upstream → Downstream)

Cellular Processes

Suggested Ontology Terms

7. Anatomical Structures Affected

Organ Level

Tissue and Cell Level

Subcellular Level

Localization

8. Temporal Development

Onset

Progression

Patterns

9. Inheritance and Population

Epidemiology

Inheritance Pattern

Population Demographics

10. Diagnostics

Clinical Case Definition (CDC, 2011 — Staphylococcal TSS)

Laboratory Tests

Genetic Testing

Imaging / Other

Differential Diagnosis

Screening

11. Outcome/Prognosis

Survival and Mortality

Morbidity and Long-Term Function

Prognostic Factors

12. Treatment

Pharmacotherapy

Advanced/Adjunctive Therapeutics

Surgical/Interventional

Supportive Care

Experimental / Preventive Immunotherapy

Treatment Algorithm Summary