Salmonella Gastroenteritis (MONDO:0005950): A Comprehensive Disease Characterization

Summary

Salmonella gastroenteritis is a self-limited, foodborne zoonotic enterocolitis caused chiefly by non-typhoidal Salmonella enterica (NTS) serovars — predominantly S. Typhimurium and S. Enteritidis — and represents one of the leading bacterial causes of diarrheal illness worldwide. The disease is fundamentally an infectious, not a genetic, entity: the initiating lesion is ingestion of Salmonella in contaminated food or water, and the causal chain runs from bacterial invasion of the distal ileal/cecal/colonic epithelium through host inflammasome activation and neutrophilic colitis to inflammatory-secretory diarrhea. A defining mechanistic insight, established across multiple lines of evidence in this investigation, is that Salmonella does not merely tolerate host inflammation but actively exploits it — inflammation oxidizes luminal thiosulfate to tetrathionate, which the pathogen uses as a respiratory electron acceptor to outcompete the fermentative resident microbiota and bloom in the gut lumen.

Clinically, most immunocompetent patients present with diarrhea (~96%), fever (~62–66%), abdominal pain (~32–42%), vomiting (~34%), and less often bloody diarrhea (~19%), after an incubation period of roughly 6–72 hours (dose-dependent), and recover spontaneously within 2–7 days with oral/IV rehydration alone. Antibiotics do not shorten uncomplicated illness and may prolong fecal carriage; they are therefore reserved for severe disease and high-risk hosts. A distinct and dangerous invasive NTS (iNTS) branch causes bacteremia and extraintestinal focal infection (mycotic aortitis, endovascular infection, osteomyelitis, meningitis) in the very young, the elderly, and immunocompromised hosts — especially those with HIV, malaria, malnutrition, anemia, sickle cell disease, or inborn errors of the IL-12/IL-23/IFN-γ axis. iNTS carries a case-fatality rate of ~15–25% and is concentrated in sub-Saharan Africa, where the multidrug-resistant S. Typhimurium ST313 lineage drives epidemics.

This report synthesizes 19 confirmed findings drawn from 94 reviewed papers, organized against the 15-section disease-characterization template. Because Salmonella gastroenteritis is an infectious disease, several template sections designed for Mendelian genetic disorders (causal genes, pathogenic variants, inheritance patterns) are not applicable in the classical sense and are reframed around host susceptibility genetics and bacterial virulence genetics, which are the biologically meaningful analogues.

1. Disease Information

Overview. Salmonella gastroenteritis is an acute inflammatory enterocolitis of the distal small bowel and colon caused by non-typhoidal serovars of the Gram-negative facultative intracellular bacterium Salmonella enterica subsp. enterica. It is the enteric-limited form of non-typhoidal salmonellosis, distinct from enteric (typhoid/paratyphoid) fever caused by the host-restricted serovars Typhi and Paratyphi.

Key identifiers. - MONDO: MONDO:0005950 (Salmonella gastroenteritis / salmonella food poisoning) - MeSH: Salmonella Infections; Salmonella Food Poisoning - ICD-10: A02.0 (Salmonella enteritis); ICD-11: 1A07 (Enteritis due to Salmonella) - SNOMED CT: Salmonella gastroenteritis - NCBI Taxonomy: Salmonella enterica (txid28901); serovar Typhimurium, serovar Enteritidis - OMIM/Orphanet: not a Mendelian disease; no primary OMIM entry (host susceptibility loci discussed in Section 4/9).

Synonyms: non-typhoidal salmonellosis, Salmonella enterocolitis, Salmonella food poisoning, NTS gastroenteritis.

Data source type. The knowledge in this report derives predominantly from aggregated disease-level resources — epidemiological surveillance (GBD, CDC, WHO), clinical cohort studies, systematic reviews, and mechanistic model-organism/in-vitro experiments — rather than from individual EHR-level patient records.

The leading global role of NTS is well documented: "Bacterial pathogens cause approximately 10-15% of episodes, most often Shigella, nontyphoidal Salmonella (NTS) Campylobacter and Shiga toxin-producing Escherichia coli (STEC)" (PMID: 35165210), and "Salmonella enterica serovar Enteritidis (S. Enteritidis) is a commonly reported pathogen which adapts to multiple hosts and causes critical disease burden at a global level" (PMID: 39855357). (Finding F001)

2. Etiology

Primary cause — infectious. The disease is caused by ingestion of viable Salmonella enterica NTS serovars. S. Typhimurium and S. Enteritidis are the most common serovars worldwide.

Environmental / lifestyle risk factors. - Contaminated food and water — poultry, eggs, dairy, beef, and produce are principal vehicles (Section 5, 12). - Gastric acid suppression. Gastric acid is a key host defense barrier. A population case-control study (6,414 cases vs 50,000 controls) found current PPI use raised bacterial gastroenteritis risk RR 2.9 (95% CI 2.5–3.5), rising to RR 5.0 with a doubled PPI dose, while H2-receptor antagonists showed no significant effect: "Current use of PPIs was associated with an increased risk of bacterial GE compared with nonuse, regardless of the treatment duration (RR, 2.9; 95% confidence interval [CI], 2.5-3.5)" (PMID: 18054750). A systematic review confirmed "PPIs appear to increase susceptibility to the following bacterial enteropathogens: Salmonella, Campylobacter jejuni, invasive strains of Escherichia coli" (PMID: 21999643). (Finding F011) - Age extremes (infants, elderly), immunocompromise (HIV), malaria, malnutrition, anemia, sickle cell disease — chiefly risk factors for the invasive branch (Section 8/9).

Host genetic risk factors. Inborn errors of the IL-12/IL-23/IFN-γ axis (Mendelian Susceptibility to Mycobacterial Disease, MSMD; >17 genes) predispose to severe/recurrent NTS. "Mendelian susceptibility to mycobacterial disease is a rare clinical condition... Other infections such as salmonellosis and candidiasis are also reported" (PMID: 28865061); "Autosomal recessive complete IL-12Rβ1 deficiency is the most frequent genetic etiology of MSMD" (PMID: 29995221). Relevant genes: IL12B, IL12RB1, IFNGR1, IFNGR2, STAT1, IL23R. In mouse models, Slc11a1 (NRAMP1) genotype strongly controls Salmonella susceptibility. (Finding F010)

Protective factors. Intact gastric acid barrier; a healthy, competitive gut microbiota (Section 6); defined-microbiota administration is protective in animal models (Section 15).

Gene–environment interaction. Susceptibility emerges from the intersection of host immune-genetic status (IL-12/IFN-γ axis, HIV, hemoglobinopathy) and environmental exposure (ingested dose, acid suppression). This interaction is most consequential for the invasive branch.

3. Phenotypes

The clinical phenotype is well characterized in pediatric cohorts:

An Istanbul pediatric cohort (n=172) reported: "The most common clinical symptoms were diarrhea (n = 166, 96.5%), fever (n = 113, 65.7%) and abdominal pain (n = 73, 42.4%). Bloody diarrhea was seen in 19.2% of patients" (PMID: 36449648). A second cohort (n=67) corroborated: "The presenting symptoms were diarrhoea (95.5%), fever (61.1%), vomiting (34.3%), abdominal pain (32.8%), loss of appetite (7.4%) and malaise (7.4%)" (PMID: 27668899). (Finding F015)

• Phenotype type: predominantly symptoms/clinical signs (diarrhea, fever, pain) plus laboratory abnormalities (elevated CRP/ESR, leukocytosis).
• Age of onset: any age; pediatric predominance in reported cohorts (median age ~59 months).
• Severity: mild-to-moderate and self-limited in immunocompetent hosts; variable.
• Progression: acute, episodic, self-limited.
• Quality of life: transient; acute illness confines patients for days (dose-dependent bed confinement, Section 8), with generally full recovery. Post-infectious reactive arthritis (Section 11) can cause lasting morbidity.

4. Genetic/Molecular Information

Salmonella gastroenteritis is not a Mendelian human genetic disease, so "causal genes," "pathogenic variants," and germline classification per ACMG do not apply in the standard sense. The biologically meaningful genetics fall into two categories:

A. Host susceptibility genes. - IL12B, IL12RB1, IFNGR1, IFNGR2, STAT1, IL23R (MSMD axis) — loss-of-function variants cause severe/disseminated salmonellosis. Documented variants include biallelic IL12RB1 C291Y (absent IFN-γ production) and an IL12B frameshift c.527_528delCT (p.S176Cfs*12) (PMID: 29995221). Functional consequence: loss of IFN-γ–dependent macrophage killing of intracellular Salmonella. (Finding F010) - SLC11A1 (NRAMP1) — divalent-cation transporter at the phagosomal membrane; genotype controls Salmonella susceptibility in mouse models (multiple Ity QTL mapped). - HLA-B27 — a major susceptibility allele for the post-infectious complication reactive arthritis (Section 11). (Finding F004)

B. Bacterial virulence genes (the true "molecular drivers" of disease): - SPI-1 (Salmonella Pathogenicity Island 1) T3SS and effectors SipA, SipB, SipC, SopB, SopE2 — drive epithelial invasion and inflammation. - SPI-2 — intracellular survival/systemic spread. - Regulators hilD, hilC, rtsA, hilA control SPI-1 expression.

No epigenetic host mechanisms, chromosomal abnormalities, or germline/somatic variant frameworks are applicable to this infectious disease.

5. Environmental Information

Infectious agent. Salmonella enterica subsp. enterica, NTS serovars — chiefly Typhimurium and Enteritidis; also S. Choleraesuis (swine-associated, invasive), S. Dublin (cattle-adapted), and reptile-associated serovars (S. Poona, S. Paratyphi B var Java, S. Agbeni, S. Cotham).

Transmission — zoonotic, fecal-oral. "Human infection occurs by fecal-oral transmission through ingestion of contaminated food, milk, or water (inter-human or zoonotic transmission)" (PMID: 31321641). Reptile reservoirs are an increasing source: "Reptile-associated outbreaks of human Salmonella infections are increasing in Canada, coinciding with a rise in the popularity of reptiles as pets" (PMID: 41017027), with documented pet-turtle→child transmission of S. Poona confirmed by identical genomic fragment patterns. (Finding F012)

Lifestyle/environmental factors. Consumption of undercooked poultry/eggs, raw dairy, contaminated produce, and contaminated water; contact with reptiles/amphibians and livestock. Multidrug resistance is rising (e.g., nalidixic acid resistance 97.67% in a Chinese S. Enteritidis collection).

6. Mechanism / Pathophysiology

Ordered causal chain

1. Ingestion of Salmonella in contaminated food/water → bacteria transit the stomach (gastric acid is a barrier; acid suppression increases risk, F011) → reach the distal ileum, cecum, and colon.
2. Bacteria access the mucosa via two portals: (a) M cells of the follicle-associated epithelium over Peyer's patches, via the GP2–FimH receptor interaction; and (b) direct invasion of enterocytes via the SPI-1 T3SS. → leads to epithelial entry.
3. SPI-1 T3SS injects effector proteins (SipA, SopE2, SopB, SipB, SipC) into host cells → results in cytoskeletal rearrangement and bacterial internalization (membrane ruffling/macropinocytosis).
4. SipB binds and activates caspase-1 → results in cleavage of pro-IL-1β to mature IL-1β (inflammasome activation).
5. Effector activity + inflammasome → drives massive neutrophil recruitment into the cecal/colonic lumen and lamina propria → acute neutrophilic colitis (SPI-1/invA-dependent).
6. SopB (inositol phosphatase) activity → causes fluid/electrolyte secretion → secretory-inflammatory diarrhea (cell death itself is not required for enteritis — an inferred but experimentally supported branch point).
7. Host inflammation → generates reactive oxygen/nitrogen species that oxidize luminal thiosulfate to tetrathionate → enables Salmonella anaerobic respiration of ethanolamine (host-derived) → luminal growth advantage over the fermentative microbiota → sustained bloom and transmission. (Finding F007)
8. Branch — invasive (iNTS): in immunocompromised/susceptible hosts (HIV, malaria, malnutrition, anemia, sickle cell, IL-12/IFN-γ axis defects), bacteria that survive within macrophages (via SPI-2) → lead to bacteremia (~5% of NTS gastroenteritis) → extraintestinal focal infection (~40% of bacteremias): mycotic aortitis, endovascular infection, osteomyelitis, meningitis. (Findings F008, F013)

Detail

Molecular pathways & effectors (F002). The SPI-1 T3SS is "a syringe-like protein injection apparatus that translocates bacterial effector proteins into host cells and is essential for epithelial invasion and early stages of pathogenesis" (PMID: 41212225). An in-vivo neonatal-mouse study showed "the critical but redundant role of SopE2 and SipA for enterocyte invasion, prerequisite for transcriptional stimulation and mucosal translocation in vivo" (PMID: 29522566). Pharmacologic T3SS inhibition (Xanthotoxol, downregulating hilD/hilC/rtsA/hilA) reduces epithelial invasion without affecting bacterial growth.

Entry portal (F014). M cells are the avid uptake portal: "GP2 interacts with FimH, a major component of the type 1 pilus on the outer membrane of a subset of gram-negative enterobacilli such as E. coli and Salmonella enterica" (PMID: 21468225), and RANKL-driven M-cell differentiation confers "avid uptake of Salmonella and Yersinia organisms" (PMID: 19828638).

Inflammasome & neutrophils (F003). "Large numbers of luminal neutrophils were observed in the ceca of WT-infected, but not in invAmut or ssaRmut infected mice" (PMID: 21327114); "SipB binds and activates caspase-1, which in turn activates the proinflammatory cytokine interleukin-1beta through cleavage" (PMID: 11402005) — and in bovine ileal loops the sopB mutant was attenuated for fluid secretion, showing effectors, not host cell death, drive enteritis.

Metabolic exploitation of inflammation (F007). "By inducing intestinal inflammation, S. Typhimurium sidesteps nutritional competition and gains the ability to use an abundant simple substrate, ethanolamine, which is provided by the host" (PMID: 21969563) — the tetrathionate-respiration mechanism is the mechanistic centerpiece of NTS colonization.

Suggested ontology terms. GO biological processes: GO:0006954 (inflammatory response), GO:0044406 (adhesion to host), GO:0052192 (movement in host), GO:0097202 (activation of cysteine-type endopeptidase/caspase-1), GO:0009410 (response to xenobiotic). Cell types (CL): CL:0000584 (enterocyte), CL:0000682 (M cell of gut), CL:0000775 (neutrophil), CL:0000235 (macrophage). Chemical entities (CHEBI): tetrathionate (CHEBI:48889), ethanolamine (CHEBI:16000).

7. Anatomical Structures Affected

• Primary organs (Organ level): distal small intestine (ileum, UBERON:0002116), cecum (UBERON:0001153), and colon (UBERON:0001155) — the digestive system.
• Secondary/complication organs: bloodstream, aorta (mycotic aortitis, UBERON:0000947), bone (osteomyelitis), meninges (meningitis), gallbladder (carriage), pancreas (rare acute pancreatitis) — in invasive disease.
• Body systems: digestive (primary); cardiovascular, skeletal, and nervous (invasive complications); immune.
• Tissue level: intestinal epithelium (follicle-associated epithelium and villous enterocytes); lamina propria (neutrophil infiltration).
• Cell populations: enterocytes (CL:0000584), M cells (CL:0000682), neutrophils (CL:0000775), macrophages (CL:0000235), goblet cells (depleted in colitis).
• Subcellular compartments (GO CC): Salmonella-containing vacuole (GO:0020005 symbiont-containing vacuole), host plasma membrane (GO:0005886), actin cytoskeleton (GO:0015629), inflammasome (GO:0061702).
• Localization/lateralization: bilateral/diffuse mucosal involvement of the distal bowel; not lateralized.

8. Temporal Development

Onset. Acute; incubation period ~6–72 hours (median ~12–38 h across outbreaks). Dose-dependent: a classic S. Enteritidis outbreak (n=169) showed "As dose increased, median incubation period decreased (37 h in the low exposure group v. 21 h in the medium exposure group v. 17.5 h in the high exposure group, P = 0.006)" (PMID: 8119352) — with higher doses also producing more vomiting, greater weight loss, more stools, and longer bed confinement. (Finding F018)

Progression & duration. Self-limited; median duration ~1–5 days (typically 2–3): "Median incubation period was 19 h (range: 3-26 h). Median duration of illness was 5 days (range: 1-11 days)" (PMID: 21824356). Convalescent fecal shedding can persist for weeks.

Course pattern. Acute, episodic, self-limited in immunocompetent hosts. Critical window for intervention: early rehydration prevents complications; for invasive disease, early susceptibility-matched antibiotics on day 0–1 improve survival (Section 12).

Chronic branch (model). Chronic murine infection produces persistent intestinal fibrosis (TGF-β1, CTGF, IGF-I upregulation; type I collagen deposition peaking day 21, present to day 70) — an inferred correlate of rare human chronic sequelae (F005).

9. Inheritance and Population

Epidemiology. NTS is a leading foodborne diarrheal pathogen. Global estimates place non-typhoidal salmonellosis at ~90+ million gastroenteritis cases/year. GBD 2021 estimated 509,976 (95%UI 413,361–606,167) incident iNTS cases in 2021: "GBD 2021 estimated 509976...incident cases of iNTS worldwide in 2021, with the most cases and highest age-standardized rate (ASR) in Western Sub-Saharan Africa" (PMID: 40168434). Foodborne bacterial pathogens (incl. NTS) caused "an estimated 364,500 deaths from diarrheal diseases (age-standardized death rate, ASDR 3.63/100,000)" (PMID: 42241982) and 24.6M DALYs in 2021. (Finding F016)

Inheritance. Not applicable — infectious, not heritable. Host susceptibility traits (MSMD axis) follow autosomal-recessive inheritance; HLA-B27 (reactive arthritis) is a co-dominant HLA allele.

Population demographics. - Age distribution: skews to young children; iNTS peaks "early in the second year of life, declining before the age of 3 years" (PMID: 40684736) and in the <1-year group by GBD. Elderly are at high risk of invasive vascular complications. - Sex ratio: slight male predominance in pediatric cohorts (M:F ~55:45). - Geographic distribution: global; invasive burden concentrated in sub-Saharan Africa and South Asia (78.7% of DALYs). S. Typhimurium ST313 drives African epidemics.

10. Diagnostics

Stool culture remains the gold standard, increasingly supplemented by multiplex PCR gastrointestinal panels (BioFire FilmArray GI, QIAstat-Dx), which detect ~23 pathogens in ~80 minutes with markedly higher yield: "QGP demonstrated a higher pathogen detection rate (42.3%; 2,033/4,801) than stool culture (12.6%; 255/2,018) and O&P examination (6.3%; 63/986)" (PMID: 42153668), with >98% negative and near-100% positive agreement. In a Saudi pediatric cohort, Salmonella was the most common pathogen detected (22.1%). (Finding F009)

Differential diagnosis: other bacterial enteritides (Shigella, Campylobacter, STEC, Yersinia), viral gastroenteritis (rotavirus, norovirus), C. difficile, inflammatory bowel disease. Multiplex panels aid discrimination but require clinical correlation given asymptomatic carriage.

11. Outcome / Prognosis

Immunocompetent hosts. Excellent prognosis; self-limited recovery in 2–7 days, negligible mortality.

Invasive NTS. High morbidity and mortality. A systematic review of Africa (1966–2014) found "NTS have been responsible for up to 39% of community acquired blood stream infections in sub-Saharan Africa with an average CFR of 19%" (PMID: 28056035). In DR Congo children <5, "overall in-hospital case fatality was 25.1% (60/239)" with 60% extensively drug-resistant (PMID: 41429348). (Findings F008, F013)

Complications. - Bacteremia: ~5% of NTS gastroenteritis; ~40% of bacteremias develop extraintestinal focal infection — "Approximately 5% of patients with NTS gastroenteritis develop bacteremia and the incidence of extra-intestinal focal infection in NTS bacteremia is about 40%" (PMID: 31321641). NTS causes ~40% of all infective aortitis; reported fatal cases include ruptured mycotic abdominal aortic aneurysm and aortoesophageal fistula (S. Choleraesuis). (Finding F013) - Reactive arthritis (post-infectious). A major sequela strongly linked to HLA-B27: in a hospitalized cohort (n=63), "HLA-B27 was present in 88%" (PMID: 9370874); in a 592-person outbreak, "HLA-B27 was present more frequently in those who developed Salmonella infection than in healthy controls (OR 3.0)" (PMID: 18528961). HLA-B27+ patients had higher ESR and were the only ones to develop sacroiliitis; 8/50 progressed to chronic spondyloarthropathy at 5–22 yr follow-up. (Finding F004) - Toxic megacolon/intestinal perforation (pediatric, rare).

Prognostic factors: host immune status, age extremes, ingested dose, serovar, antimicrobial susceptibility, presence of endovascular/prosthetic material, severe anemia.

12. Treatment

Core principle. Uncomplicated Salmonella gastroenteritis is managed with rehydration alone; antibiotics are reserved for severe/high-risk cases and invasive disease. European ESPID/ESPGHAN guidance: "There is no argument to treat moderate salmonella gastroenteritis or carriage. However, the severe cases and those occurring in high risk patient must be treated (ciprofloxacin or ceftriaxone)" (PMID: 19000862). Antibiotics do not shorten uncomplicated illness and may prolong carriage. (Finding F017)

High-risk groups warranting therapy: infants <3 months, elderly, immunocompromised (HIV, MSMD), hemoglobinopathy, and patients with prosthetic/endovascular grafts.

Susceptibility-guided therapy is critical for invasive disease. In DR Congo children, "susceptibility-matched third-generation cephalosporin treatment on hospital day 0-1 had better 14-day in-hospital survival" (PMID: 41429348); with extensive drug resistance in 60% of isolates, empiric mismatches worsen outcomes.

No gene, cell, or RNA-based therapies apply. Surgical intervention (graft excision, aneurysm repair) is required for endovascular complications.

13. Prevention

Primary prevention centers on food and water safety. "Proper food and water treatment, better sanitary facilities, public awareness campaigns, and adherence to food safety laws are all part of prevention measures" (PMID: 38021876). Key measures: safe food handling/cooking (poultry, eggs), pasteurization, hand hygiene, reptile-contact precautions, and One Health surveillance of animal reservoirs and antimicrobial resistance. (Finding F006)

Vaccination. No licensed human NTS vaccine exists. Candidates in preclinical/animal development include: - Live attenuated strains — e.g., ΔmanA ΔsteD (RAST002): "Protective efficacy was assessed through challenge studies, demonstrating up to 80% protection against the homologous strain" (PMID: 41398587) (60–80% heterologous). - Outer-membrane vesicle (OMV) vaccines. - Probiotic-derived antimicrobial peptides.

Prevention levels. Primary — food/water safety, (future) vaccination, gastric-acid preservation (avoid unnecessary PPIs in at-risk patients). Secondary — early rehydration and diagnosis. Tertiary — susceptibility-guided antibiotics and surveillance for endovascular complications in bacteremic patients. Public-health: sanitation, health education, livestock/reptile reservoir control.

14. Other Species / Natural Disease

Salmonella gastroenteritis is fundamentally zoonotic, with broad animal reservoirs.

• Taxonomy: Salmonella enterica subsp. enterica (NCBI txid59201); serovars Typhimurium, Enteritidis, Dublin, Choleraesuis.
• Reservoir species: poultry and eggs, cattle, pigs (S. Choleraesuis), and reptiles/amphibians (turtles, snakes, bearded dragons).
• Natural disease in animals. S. Dublin is a cattle-adapted (host-restricted) serovar causing bovine salmonellosis (systemic disease, abortion, calf enteritis) and serving as a reservoir for human invasive NTS. WGS links human isolates to dairy-cattle isolates and interstate cattle movement (PMID: 42742664; PMID: 42308994). Salmonella is detectable in bovine deep-tissue lymph nodes (~10.8% pooled prevalence) and cow milk (~9.56%), providing zoonotic exposure routes. (Finding F019)
• Comparative pathology: broad-host-range serovars (Typhimurium, Enteritidis) dominate human sporadic gastroenteritis, whereas host-adapted serovars (Dublin–cattle, Choleraesuis–swine) tend toward invasive disease.
• Zoonotic transmission: reptile-associated salmonellosis with serovar-specificity (S. Paratyphi B var Java–snakes; S. Agbeni–turtles; S. Cotham/Chester/Tennessee–bearded dragons) is well documented and rising (PMID: 41017027). (Finding F012)

15. Model Organisms

The streptomycin-pretreated mouse colitis model is the principal system recapitulating human Salmonella gastroenteritis. Streptomycin pretreatment of C57BL/6 mice before oral S. Typhimurium produces cecal/colonic colonization with acute neutrophilic mucosal inflammation, edema, epithelial damage, and goblet-cell depletion. (Finding F005)

• MyD88 (TLR adaptor) is required for full mucosal inflammation and drives fibrosis: "they were impaired in the development of mucosal inflammation" (PMID: 22679002).
• Chronic model: "Infection led to chronic Salmonella colonization of the cecum and colon followed by edema, mucosal ulcerations, and severe transmural inflammation" (PMID: 18325390), with persistent fibrosis.
• Microbiota protection: defined microbiota MET-1 protects — "Infected mice receiving MET-1 lost less weight, had reduced serum cytokines, reduced NF-κB nuclear staining, and decreased neutrophil infiltration in the cecum" (PMID: 26531327) — by preserving tight junctions and reducing systemic translocation without lowering intestinal CFU.

Other systems: neonatal mouse (enterocyte invasion, F002); bovine ileal loop (fluid secretion, effector dependence, F003); calf enteritis (S. Dublin); in-vitro Caco-2/Raji M-cell co-culture (M-cell translocation, F014); HeLa/epithelial invasion assays.

Model types: mammalian (mouse, calf), cellular/in-vitro (Caco-2/Raji, HeLa). Genetic models: MyD88−/−, Slc11a1 (Nramp1) congenic strains, IL-12/IFN-γ axis knockouts.

Phenotype recapitulation. The streptomycin mouse reproduces neutrophilic colitis, microbiota disruption, tetrathionate-driven blooming, and (chronically) fibrosis. Limitations: requires antibiotic pretreatment (mice are naturally colitis-resistant); the streptomycin model mimics human enterocolitis but not the human-restricted typhoid syndrome; does not fully capture human iNTS host-genetic diversity.

Mechanistic Model / Interpretation

 INGESTION (contaminated food/water) ── gastric acid barrier (down by PPIs, F011)
        |
        v
 DISTAL ILEUM / CECUM / COLON
        |
   +----+-----------------------------+
   v                                  v
 M CELLS (GP2-FimH, F014)     ENTEROCYTES (SPI-1 T3SS: SipA/SopE2/SopB, F002)
   |                                  |
   +----------------+-----------------+
                    v
        SipB -> caspase-1 -> IL-1beta (inflammasome, F003)
                    v
        NEUTROPHIL COLITIS + SopB-driven fluid secretion (F003)
                    v
        INFLAMMATION oxidizes thiosulfate -> TETRATHIONATE
                    v
        Salmonella respires ETHANOLAMINE -> LUMINAL BLOOM (F007)
                    v
        INFLAMMATORY-SECRETORY DIARRHEA (self-limited, 2-7 d, F015/F018)
                    |
                    v (susceptible host: HIV/malaria/malnutrition/anemia/SCD/IL-12-IFNg, F008/F010)
        MACROPHAGE SURVIVAL (SPI-2) -> BACTEREMIA (~5%)
                    v
        FOCAL INFECTION (~40%): mycotic aortitis, osteomyelitis, meningitis (F013)
                    |
                    v (post-infectious, HLA-B27, F004)
        REACTIVE ARTHRITIS / spondyloarthropathy

The central, distinguishing insight is that Salmonella weaponizes host inflammation: rather than a bystander, inflammation supplies a unique anaerobic electron acceptor (tetrathionate) and nutrient (ethanolamine) that the pathogen alone can exploit, converting the host defense into a competitive advantage. This "inflammation-as-nutrient-niche" paradigm unifies the invasion (SPI-1), inflammasome, and microbiota-bloom findings into a single coherent narrative and explains why the disease is simultaneously inflammatory and self-limited in immunocompetent hosts, while diverging into a lethal invasive branch when macrophage-based control (IFN-γ axis) fails.

Evidence Base

Limitations and Knowledge Gaps

1. Template–disease mismatch. The disease-characterization template is designed for Mendelian genetic disorders. Sections on causal genes, pathogenic variant classification (ACMG/AMP), inheritance patterns, penetrance, and germline/somatic origin are not applicable to an infectious disease and were reframed around host susceptibility and bacterial virulence genetics.
2. Mechanistic evidence is largely from model organisms. The SPI-1 invasion, inflammasome, tetrathionate-bloom, and M-cell findings derive chiefly from mouse, calf, and in-vitro models; direct human intestinal mechanistic validation is limited.
3. Symptom-frequency data come predominantly from pediatric cohorts (Istanbul, Turkey), which may not generalize to adults or to different serovar distributions.
4. iNTS burden and CFR rely on regional African surveillance with heterogeneous diagnostics; global iNTS estimates carry wide uncertainty intervals.
5. No licensed human vaccine; efficacy data are preclinical/murine.
6. Quality-of-life and long-term functional outcome data (per-phenotype) are sparse for the acute self-limited illness; better characterized only for reactive arthritis sequelae.
7. Antimicrobial resistance dynamics (e.g., ST313, 3rd-gen cephalosporin resistance) are evolving rapidly and region-specific.

Proposed Follow-up Experiments / Actions

1. Human mucosal validation of the tetrathionate/ethanolamine niche using ex-vivo human intestinal organoids or biopsy-derived enteroids challenged with S. Typhimurium, measuring luminal tetrathionate and ethanolamine-utilization genes.
2. Prospective adult and mixed-serovar cohorts to refine symptom frequencies, complication rates, and quality-of-life metrics beyond pediatric data.
3. Advance NTS vaccine candidates (RAST002 live-attenuated, OMV) into early-phase human trials, prioritizing sub-Saharan African pediatric populations at highest iNTS risk.
4. Host-genetic screening study correlating IL-12/IFN-γ axis variants (IL12RB1, IL12B, IFNGR1/2, STAT1) and SLC11A1 genotypes with invasive-disease risk in prospective iNTS cohorts.
5. Antimicrobial stewardship & resistance surveillance integrated with multiplex-PCR diagnostics to guide susceptibility-matched therapy and track ST313 spread.
6. One Health interventions targeting the S. Dublin cattle-movement transmission network and reptile reservoirs, using WGS-based source attribution.
7. Therapeutics targeting the inflammation-niche axis (e.g., tetrathionate-pathway or SPI-1 T3SS inhibitors such as Xanthotoxol) as anti-virulence adjuncts that reduce microbiota disruption.

Report compiled from 19 confirmed findings across 5 investigation iterations and 94 reviewed papers. Evidence source types span human clinical cohorts/surveillance, model-organism (mouse, calf) experiments, and in-vitro cellular studies, as annotated throughout.