Pneumonia Caused By Pseudomonas Aeruginosa Infection

Infectious Disease MONDO:0037398 Pathograph 14 Show in embeddings browser Pseudomonas aeruginosa infectious disease

Pneumonia caused by Pseudomonas aeruginosa infection is an acute bacterial lower-respiratory infection in which the opportunistic Gram-negative bacillus Pseudomonas aeruginosa reaches the distal airways or ventilated alveolar compartment, senses and injures epithelial and macrophage surfaces through flagellin, a type III secretion system, and cytotoxic effectors, and drives a suppurative neutrophilic pneumonia that can progress to alveolar-capillary barrier failure, sepsis, and ventilator-associated multidrug-resistant disease. In structurally abnormal airways, especially cystic fibrosis or bronchiectasis, mucoid alginate biofilm formation creates a chronic phagocytosis-resistant branch of infection.

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Classifications

Harrison's Part
INFECTIOUS DISEASES
⚙

Pathophysiology

7
Lower-Airway Pseudomonas Infection
P. aeruginosa enters the distal airway or ventilated alveolar compartment and establishes lower-respiratory infection, bringing flagellin, type III secretion injectisomes, and cytotoxic effector proteins into contact with alveolar epithelial and innate immune cells.
lung UBERON:0002048 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in lung (UBERON:0002048). UBERON:0002048 is an anatomical location from the Uberon multi-species anatomy ontology. alveolus of lung UBERON:0002299 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in alveolus of lung (UBERON:0002299). UBERON:0002299 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Airway Flagellin-TLR5 Signaling Flagellated bacilli are sensed by epithelial TLR5 when they contact the airway surface.
Type III Secretion Cytotoxicity Bacterial contact permits the type III secretion apparatus to inject Exo-family cytotoxic effectors into host cells.
NLRC4 Inflammasome IL-1 Beta Release Alveolar macrophages sense the type III secretion apparatus and activate an NLRC4 inflammasome response.
Show evidence (1 reference)
PMID:35022730 SUPPORT PRIMARY RESULT Human clinical
"Baseline LRT pathogens included Klebsiella pneumoniae (34.6%), Pseudomonas aeruginosa (25.0%) and Escherichia coli (18.2%)."
Supports the lower respiratory tract as the infected site in P. aeruginosa hospital-acquired and ventilator-associated pneumonia.
Airway Flagellin-TLR5 Signaling
Airway epithelial cells recognize P. aeruginosa flagellin through TLR5, initiating NF-kB-linked inflammatory signaling that helps launch the neutrophilic response to lower-airway infection.
epithelial cell CL:0000066 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves epithelial cell (CL:0000066). CL:0000066 is a cell type from the Cell Ontology.
toll-like receptor signaling pathway GO:0002224 ↑ INCREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased toll-like receptor signaling pathway (GO:0002224). GO:0002224 is a biological process from the Gene Ontology. inflammatory response GO:0006954 ↑ INCREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology.
Downstream
Neutrophilic Alveolar-Capillary Injury Flagellin sensing induces epithelial inflammatory mediators that converge with T3SS and inflammasome signals to recruit neutrophils.
Show evidence (1 reference)
PMID:16239509 SUPPORT PRIMARY RESULT In vitro / ex vivo
"airway epithelial receptor TLR5 senses P. aeruginosa through its flagellin protein"
Shows that human airway epithelial cells use TLR5 to detect P. aeruginosa flagellin.
Type III Secretion Cytotoxicity
The P. aeruginosa type III secretion system injects ExoU, ExoS, ExoT, and ExoY effector proteins into contacted epithelial and innate immune cells, producing a cytotoxic acute-lung-injury phenotype.
pulmonary alveolar type 2 cell CL:0002063 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves pulmonary alveolar type 2 cell (CL:0002063). CL:0002063 is a cell type from the Cell Ontology.
Animal models
T3SS-competent rat acute lung injury model Rattus norvegicus recapitulates Comparing a wild-type T3SS strain to an exsA-null mutant isolates the type III secretion contribution to alveolar permeability injury.
Downstream
NLRC4 Inflammasome IL-1 Beta Release The type III secretion apparatus can be sensed by macrophages and activate an NLRC4 inflammasome response.
Neutrophilic Alveolar-Capillary Injury T3SS-competent organisms directly worsen epithelial cytotoxicity, alveolar permeability, bacterial clearance, and mortality in acute lung injury.
Show evidence (1 reference)
PMID:15972518 SUPPORT PRIMARY RESULT In vitro / ex vivo
"the CHA strain was associated with increased in vitro cytotoxicity on A549 cells, as assessed by the release of lactate dehydrogenase"
A functional type III secretion system (CHA strain) produced greater host-cell cytotoxicity than its isogenic exsA-null mutant, supporting T3SS-driven cytotoxicity.
NLRC4 Inflammasome IL-1 Beta Release
Alveolar macrophages exposed to T3SS-expressing P. aeruginosa activate the NLRC4 inflammasome and produce IL-1 beta, an inflammatory axis that can impair macrophage phagocytosis and intensify lung injury.
alveolar macrophage CL:0000583 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves alveolar macrophage (CL:0000583). CL:0000583 is a cell type from the Cell Ontology.
interleukin-1 beta production GO:0032611 ↑ INCREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased interleukin-1 beta production (GO:0032611). GO:0032611 is a biological process from the Gene Ontology. phagocytosis GO:0006909 ↓ DECREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased phagocytosis (GO:0006909). GO:0006909 is a biological process from the Gene Ontology.
Downstream
Neutrophilic Alveolar-Capillary Injury Inflammasome-driven IL-1 beta release amplifies cytokine production, phagocytic failure, and pulmonary inflammatory damage.
Show evidence (1 reference)
PMID:33489931 SUPPORT PRIMARY RESULT Model organism
"PA infection mainly activated Nod-like receptor containing a caspase activating and recruitment domain 4 (NLRC4) inflammasome"
Supports NLRC4 inflammasome activation in experimental acute P. aeruginosa lung infection.
Mucoid Alginate Biofilm Immune Evasion
In chronic airway infection, mucoid P. aeruginosa overproduces cell-surface alginate and grows as biofilm, physically interfering with opsonic and non-opsonic macrophage phagocytosis and helping the organism persist in cystic-fibrosis or bronchiectatic airways.
biofilm formation GO:0042710 ↑ INCREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased biofilm formation (GO:0042710). GO:0042710 is a biological process from the Gene Ontology. phagocytosis GO:0006909 ↓ DECREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves decreased phagocytosis (GO:0006909). GO:0006909 is a biological process from the Gene Ontology.
Downstream
Chronic Pseudomonas Airway Persistence Alginate-mediated antiphagocytic biofilm growth promotes persistence after mucoid conversion in structurally abnormal airways.
Show evidence (1 reference)
PMID:37009499 SUPPORT PRIMARY RESULT In vitro / ex vivo
"alginate production inhibited opsonic and non-opsonic phagocytosis"
Demonstrates that bacterial surface alginate blocks human and murine macrophage phagocytosis of mucoid P. aeruginosa.
Chronic Pseudomonas Airway Persistence
Mucoid biofilm immune evasion allows P. aeruginosa to persist in airways with cystic-fibrosis or bronchiectatic mucus clearance defects, converting a hospital-style acute Gram-negative pneumonia mechanism into a relapsing chronic infection pattern.
lung UBERON:0002048 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in lung (UBERON:0002048). UBERON:0002048 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Neutrophilic Alveolar-Capillary Injury Persistent infection repeatedly exposes the airway to Pseudomonas ligands, cytotoxins, and neutrophilic inflammatory injury.
Show evidence (1 reference)
PMID:37009499 SUPPORT BACKGROUND Human clinical
"During chronic colonization of the airway and biofilm formation, P. aeruginosa converts to a mucoid phenotype"
The study's introduction restates the established clinical natural history of chronic P. aeruginosa airway colonization, in which the organism converts to a mucoid phenotype.
Neutrophilic Alveolar-Capillary Injury
Epithelial TLR5 signaling, macrophage NLRC4/IL-1 beta activation, and T3SS cytotoxicity converge on a neutrophilic inflammatory exudate that injures the alveolar-capillary barrier, causes protein-rich edema, and can progress to acute respiratory failure, sepsis, and death.
neutrophil CL:0000775 Cell Ontology (CL) Relation: this pathophysiological event involves this cell type This pathophysiological event involves neutrophil (CL:0000775). CL:0000775 is a cell type from the Cell Ontology.
inflammatory response GO:0006954 ↑ INCREASED Gene Ontology (GO) Relation: this pathophysiological event involves this biological process This pathophysiological event involves increased inflammatory response (GO:0006954). GO:0006954 is a biological process from the Gene Ontology.
alveolus of lung UBERON:0002299 Uberon multi-species anatomy ontology (UBERON) Relation: this pathophysiological event occurs in this anatomical location This pathophysiological event occurs in alveolus of lung (UBERON:0002299). UBERON:0002299 is an anatomical location from the Uberon multi-species anatomy ontology.
Downstream
Dyspnea Alveolar-capillary barrier failure and protein-rich edema impair gas exchange, producing dyspnea.
Acute respiratory distress syndrome Diffuse neutrophilic alveolar injury and permeability edema can progress to acute respiratory distress syndrome physiology.
Sepsis Severe lower-respiratory injury with invasive infection can disseminate or drive a systemic inflammatory response, causing sepsis.
Show evidence (1 reference)
PMID:15972518 SUPPORT PRIMARY RESULT Model organism
"increased lung injury, as assessed by the wet/dry weight ratio for the lungs and the protein level in bronchoalveolar lavage fluid"
Supports edema and alveolar protein leak as readouts of T3SS-amplified acute lung injury in a P. aeruginosa pneumonia model.
⬡

Pathograph

Use Group by to collapse related nodes into one box. Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Pneumonia Caused By Pseudomonas Aeruginosa Infection Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

7
Blood 1
Increased total leukocyte count Common HP:0001974 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Increased total leukocyte count (HP:0001974). HP:0001974 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged mechanical ventilation were associated with VAP."
Supports leukocytosis as a clinical correlate of ventilator-associated pneumonia.
Immune 2
Acute respiratory distress syndrome Subset HP:0033677 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Acute respiratory distress syndrome (HP:0033677). HP:0033677 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:15972518 SUPPORT INDIRECT PRIMARY RESULT Model organism
"increased lung injury, as assessed by the wet/dry weight ratio for the lungs and the protein level in bronchoalveolar lavage fluid"
Supports the Pseudomonas T3SS as a driver of permeability-type acute lung injury, the experimental counterpart of severe ARDS progression; the inference from the rat model to human ARDS is indirect.
PMID:42807670 SUPPORT INDIRECT PRIMARY RESULT Human clinical
"he developed fever, copious purulent secretions, and acute respiratory failure requiring ICU admission and MV."
Documents acute respiratory failure requiring mechanical ventilation in a human patient with P. aeruginosa pneumonia, the severe respiratory endpoint of which ARDS is the most severe form.
Sepsis Subset HP:0100806 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Sepsis (HP:0100806). HP:0100806 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:15972518 SUPPORT BACKGROUND Human clinical
"more likely to develop bacteremia, septic shock, and multiple organ failure"
The study's introduction restates the human clinical observation that ventilator-acquired P. aeruginosa pneumonia frequently progresses to bacteremia and septic shock.
Metabolism 2
Fever Common HP:0001945 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Fever (HP:0001945). HP:0001945 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:42807670 SUPPORT PRIMARY RESULT Human clinical
"he developed fever, copious purulent secretions, and acute respiratory failure requiring ICU admission and MV."
Documents fever in a critically ill patient with multidrug-resistant P. aeruginosa ventilator-associated pneumonia.
Elevated circulating C-reactive protein concentration Common HP:0011227 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Elevated circulating C-reactive protein concentration (HP:0011227). HP:0011227 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"CRP demonstrated good-to-moderate discriminative ability for VAP"
Supports elevated CRP as an inflammatory marker used to discriminate ventilator-associated pneumonia.
Respiratory 2
Purulent tracheal secretions Common Abnormal sputum HP:0032016 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Purulent tracheal secretions, annotated with Abnormal sputum (HP:0032016). HP:0032016 is a phenotype from the Human Phenotype Ontology.
Show evidence (1 reference)
PMID:35022730 SUPPORT PRIMARY RESULT Human clinical
"purulent tracheal secretions with ≥1 other clinical criterion"
Purulent tracheal secretions are a required diagnostic criterion for ventilated HAP/VAP in the ASPECT-NP trial population.
Dyspnea Common HP:0002094 Human Phenotype Ontology (HP) Relation: this clinical feature is this phenotype This clinical feature is Dyspnea (HP:0002094). HP:0002094 is a phenotype from the Human Phenotype Ontology.
Show evidence (2 references)
PMID:15972518 SUPPORT INDIRECT PRIMARY RESULT Model organism
"increased lung injury, as assessed by the wet/dry weight ratio for the lungs and the protein level in bronchoalveolar lavage fluid"
Supports alveolar permeability injury as the physiologic basis for respiratory compromise in T3SS-positive P. aeruginosa pneumonia; the inference from the rat model to human dyspnea is indirect.
PMID:42807670 SUPPORT PRIMARY RESULT Human clinical
"he developed fever, copious purulent secretions, and acute respiratory failure requiring ICU admission and MV."
Documents acute respiratory failure in a human patient with P. aeruginosa ventilator-associated pneumonia.
💊

Medical Actions

2
Susceptibility-guided antipseudomonal beta-lactam therapy
Action: Antibiotic TherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Antibiotic Therapy (NCIT:C15620). NCIT:C15620 is a clinical intervention from the NCI Thesaurus. NCIT:C15620
Agent: ceftolozane CHEBI:134719 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses ceftolozane (CHEBI:134719). CHEBI:134719 is a therapeutic agent from Chemical Entities of Biological Interest. tazobactam CHEBI:9421 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses tazobactam (CHEBI:9421). CHEBI:9421 is a therapeutic agent from Chemical Entities of Biological Interest. meropenem CHEBI:43968 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses meropenem (CHEBI:43968). CHEBI:43968 is a therapeutic agent from Chemical Entities of Biological Interest.
Platform: Small molecule
Ventilated hospital-acquired or ventilator-associated P. aeruginosa pneumonia is treated with an antipseudomonal antibiotic regimen guided by isolate susceptibility, local resistance, severity, and renal function; the ASPECT-NP trial compared ceftolozane/tazobactam with meropenem in a Gram-negative HAP/VAP population that included P. aeruginosa.
Mechanism Target:
INHIBITS Lower-Airway Pseudomonas Infection — Active antipseudomonal therapy kills or suppresses the lower-respiratory P. aeruginosa population driving pneumonia.
INHIBITS Neutrophilic Alveolar-Capillary Injury — Bacterial clearance removes the trigger for ongoing neutrophilic alveolar barrier injury.
Show evidence (1 reference)
PMID:35022730 SUPPORT PRIMARY RESULT Human clinical
"Mechanically ventilated participants with hospital-acquired/ventilator-associated bacterial pneumonia were randomized"
Supports randomized treatment of ventilated HAP/VAP with ceftolozane/tazobactam or meropenem, a trial population in which P. aeruginosa was a common baseline lower-respiratory pathogen.
Adjunctive inhaled colistin-aminoglycoside therapy for selected MDR cases
Action: Antibiotic TherapyNCI Thesaurus (NCIT) Relation: this treatment is this clinical intervention This treatment is Antibiotic Therapy (NCIT:C15620). NCIT:C15620 is a clinical intervention from the NCI Thesaurus. NCIT:C15620
Agent: colistin CHEBI:37943 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses colistin (CHEBI:37943). CHEBI:37943 is a therapeutic agent from Chemical Entities of Biological Interest. amikacin CHEBI:2637 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses amikacin (CHEBI:2637). CHEBI:2637 is a therapeutic agent from Chemical Entities of Biological Interest. tobramycin CHEBI:28864 Chemical Entities of Biological Interest (CHEBI) Relation: this treatment uses this therapeutic agent This treatment uses tobramycin (CHEBI:28864). CHEBI:28864 is a therapeutic agent from Chemical Entities of Biological Interest.
Platform: Small molecule
Critically ill patients with MDR P. aeruginosa HAP/VAP may receive inhaled colistin followed by an inhaled aminoglycoside as adjunctive local therapy on top of systemic antibiotics when conventional systemic options are limited, but this remains a selected-case MDR strategy rather than a universal first-line regimen.
Mechanism Target:
INHIBITS Lower-Airway Pseudomonas Infection — Nebulized polymyxin and aminoglycoside delivery attempts to achieve high intrapulmonary concentrations against MDR organisms in the infected lung.
Show evidence (1 reference)
PMID:42807670 SUPPORT PRIMARY RESULT Human clinical
"We describe three critically ill patients with HAP/VAP due to MDR PA."
Documents adjunctive inhaled colistin plus amikacin or tobramycin in critically ill MDR P. aeruginosa HAP/VAP cases.
🌍

Environmental Factors

1
Mechanical ventilation and ICU airway instrumentation
Endotracheal intubation, repeated airway manipulation, impaired mucociliary clearance, and prolonged ventilation create a hospital lower-airway exposure niche in which P. aeruginosa can reach the distal respiratory tract.
Show evidence (1 reference)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged mechanical ventilation were associated with VAP."
Supports mechanical ventilation and reintubation as acquisition contexts for ventilator-associated pneumonia.
Mechanism Target:
TRIGGERS Lower-Airway Pseudomonas Infection — Ventilation and airway instrumentation bypass upper-airway defenses and permit P. aeruginosa to seed the tracheobronchial tree and alveolar compartment.
🔬

Diagnosis

2
Lower-respiratory culture with antimicrobial susceptibility testing
Pseudomonas pneumonia is confirmed by culturing lower-respiratory samples, such as endotracheal aspirate or bronchoalveolar lavage fluid, and testing antimicrobial susceptibility because MDR and carbapenem-resistant isolates are common in hospital-acquired disease.
Show evidence (2 references)
PMID:42801252 SUPPORT PRIMARY RESULT Human clinical
"Endotracheal aspirate samples were cultured, and antimicrobial susceptibility testing was performed"
Supports endotracheal aspirate culture followed by antimicrobial susceptibility testing in patients with ventilator-associated pneumonia.
PMID:41826861 SUPPORT PRIMARY RESULT Human clinical
"period prevalence calculated within total isolates of each organism group was highest for MDR-CR Acinetobacter (22.8%), followed by MDR-CR P. aeruginosa (12.9%)"
Supports that multidrug-resistant, carbapenem-resistant P. aeruginosa isolates are common, motivating antimicrobial susceptibility testing; the figure is a resistance proportion among isolates, not disease prevalence.
CRP and leukocyte inflammatory-marker support
Elevated CRP and leukocytosis support the clinical diagnosis and risk assessment of ventilator-associated pneumonia but do not identify P. aeruginosa without microbiology.
Markers: C-reactive protein; leukocyte count
Show evidence (1 reference)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"CRP demonstrated good-to-moderate discriminative ability for VAP"
Supports CRP as a discriminating inflammatory biomarker for VAP in an ICU cohort.
📈

Progression

2
Acute ventilator-associated pneumonia
Acute lower-airway P. aeruginosa infection in a ventilated or impaired airway drives flagellin- and T3SS-mediated neutrophilic pneumonia that can progress to alveolar-capillary barrier failure, respiratory failure, and sepsis.
Show evidence (1 reference)
PMID:35022730 SUPPORT PRIMARY RESULT Human clinical
"purulent tracheal secretions with ≥1 other clinical criterion"
Defines the acute ventilated-pneumonia presentation in the trial population.
Chronic mucoid airway infection
In structurally abnormal airways (cystic fibrosis, bronchiectasis), P. aeruginosa converts to a mucoid alginate-overproducing phenotype and establishes a relapsing, phagocytosis-resistant chronic airway infection.
Show evidence (1 reference)
PMID:37009499 SUPPORT BACKGROUND Human clinical
"During chronic colonization of the airway and biofilm formation, P. aeruginosa converts to a mucoid phenotype"
Describes the chronic mucoid-conversion phase of P. aeruginosa airway infection.
📊

Prevalence

1
Mechanically ventilated patients, Tuzla tertiary-care ICU
Period prevalence
VAP occurred in 34.7% of mechanically ventilated patients in this cohort, with Gram-negative pathogens predominating and P. aeruginosa the second-ranked causative pathogen. This is overall VAP occurrence in the ventilated cohort, not P. aeruginosa-specific disease prevalence, so no disease-specific rate is asserted in the structured slots.
Show evidence (1 reference)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"VAP was diagnosed in 41 patients (34.7%)."
Reports the proportion of mechanically ventilated patients who developed VAP in a cohort where P. aeruginosa was the second-ranked pathogen.
🦠

Infectious Agent

1
Pseudomonas aeruginosa
Pseudomonas aeruginosa is the Gram-negative nonfermenting rod that defines this pneumonia subtype.
Pseudomonas aeruginosa NCBITaxon:287 NCBI Taxonomy (NCBITaxon)
Show evidence (1 reference)
PMID:35022730 SUPPORT PRIMARY RESULT Human clinical
"Baseline LRT pathogens included Klebsiella pneumoniae (34.6%), Pseudomonas aeruginosa (25.0%) and Escherichia coli (18.2%)."
Demonstrates that P. aeruginosa is a recovered lower-respiratory tract pathogen in hospital-acquired and ventilator-associated bacterial pneumonia.
↔️

Transmission

1
Hospital lower-airway acquisition
P. aeruginosa pneumonia is commonly acquired when hospital or ICU exposures place the organism into an intubated or impaired lower airway, especially after mechanical ventilation, reintubation, prolonged ICU care, or prior antibiotic selection for resistant strains.
Show evidence (2 references)
PMID:42592972 SUPPORT PRIMARY RESULT Human clinical
"Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged mechanical ventilation were associated with VAP."
Links invasive airway support and its duration to ventilator-associated pneumonia, the major clinical context for Pseudomonas lower-respiratory infection.
PMID:41826861 SUPPORT PRIMARY RESULT Human clinical
"Hospitals were the primary source of MDR-CR isolates"
Supports the hospital reservoir for multidrug-resistant carbapenem-resistant P. aeruginosa and other Gram-negative isolates.
🔬

Clinical Trials

1
NCT02070757 PHASE_III COMPLETED
ASPECT-NP: a Phase 3 randomized, double-blind trial comparing intravenous ceftolozane/tazobactam with meropenem in adults with ventilated hospital-acquired or ventilator-associated bacterial pneumonia.
Show evidence (1 reference)
clinicaltrials:NCT02070757 SUPPORT PRIMARY RESULT Human clinical
"This is a phase 3, multicenter, prospective, randomized study of intravenous (IV) ceftolozane/tazobactam versus IV meropenem in the treatment of adult participants with either ventilator-associated bacterial pneumonia (VABP) or ventilated hospital-acquired bacterial pneumonia (HABP)."
Establishes the ASPECT-NP trial of ceftolozane/tazobactam versus meropenem for ventilated nosocomial pneumonia.
🐁

Animal Models

1
T3SS-competent rat acute lung injury model
Rats challenged intratracheally with a T3SS-competent P. aeruginosa CHA strain developed greater alveolar permeability injury, impaired bacterial clearance, and higher mortality than rats challenged with the isogenic exsA-null CHA-D1 strain, directly testing T3SS contribution to acute Pseudomonas lung injury.
Pseudomonas acute lung injury Elevated bronchoalveolar lavage protein Increased lung wet/dry weight ratio
Species
Rattus norvegicus
Genotype
Wild type
Publication
PMID:15972518
Pathograph links
Type III Secretion Cytotoxicity recapitulates fidelity: high observes: tissue Comparing a wild-type T3SS strain to an exsA-null mutant isolates the type III secretion contribution to alveolar permeability injury.
Show evidence (1 reference)
PMID:15972518 SUPPORT PRIMARY RESULT Model organism
"increased lung injury, as assessed by the wet/dry weight ratio for the lungs and the protein level in bronchoalveolar lavage fluid"
Shows that the T3SS-competent challenge produced more permeability edema than the T3SS-deficient mutant.
Show evidence (1 reference)
PMID:15972518 SUPPORT PRIMARY RESULT Model organism
"decreased bacterial clearance from the lungs, ultimately leading to an increased mortality rate"
Supports bacterial-clearance and mortality phenotypes in the T3SS-competent rat acute lung injury model.
{ }

Source YAML

click to show 
name: Pneumonia Caused By Pseudomonas Aeruginosa Infection
creation_date: "2026-09-30T09:04:44Z"
description: >-
  Pneumonia caused by Pseudomonas aeruginosa infection is an acute bacterial
  lower-respiratory infection in which the opportunistic Gram-negative bacillus
  Pseudomonas aeruginosa reaches the distal airways or ventilated alveolar
  compartment, senses and injures epithelial and macrophage surfaces through
  flagellin, a type III secretion system, and cytotoxic effectors, and drives a
  suppurative neutrophilic pneumonia that can progress to alveolar-capillary
  barrier failure, sepsis, and ventilator-associated multidrug-resistant
  disease. In structurally abnormal airways, especially cystic fibrosis or
  bronchiectasis, mucoid alginate biofilm formation creates a chronic
  phagocytosis-resistant branch of infection.
category: Infectious Disease
classifications:
  harrisons_chapter:
  - classification_value: INFECTIOUS_DISEASES
    evidence:
    - reference: PMID:35022730
      reference_title: >-
        Clinical and microbiological outcomes, by causative pathogen, in the
        ASPECT-NP randomized, controlled, Phase 3 trial comparing
        ceftolozane/tazobactam and meropenem for treatment of
        hospital-acquired/ventilator-associated bacterial pneumonia.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: >-
        Baseline LRT pathogens included Klebsiella pneumoniae (34.6%),
        Pseudomonas aeruginosa (25.0%) and Escherichia coli (18.2%).
      explanation: >-
        Identifies P. aeruginosa as a lower-respiratory pathogen among
        ventilated patients with hospital-acquired or ventilator-associated
        bacterial pneumonia, placing this disorder in the infectious-disease
        part.
disease_term:
  preferred_term: pneumonia caused by pseudomonas aeruginosa infection
  term:
    id: MONDO:0037398
    label: pneumonia caused by pseudomonas aeruginosa infection
parents:
- Pseudomonas aeruginosa infectious disease
synonyms:
- Pseudomonas aeruginosa pneumonia
- pseudomonal pneumonia
infectious_agent:
- name: Pseudomonas aeruginosa
  description: >-
    Pseudomonas aeruginosa is the Gram-negative nonfermenting rod that defines
    this pneumonia subtype.
  infectious_agent_term:
    preferred_term: Pseudomonas aeruginosa
    term:
      id: NCBITaxon:287
      label: Pseudomonas aeruginosa
  evidence:
  - reference: PMID:35022730
    reference_title: >-
      Clinical and microbiological outcomes, by causative pathogen, in the
      ASPECT-NP randomized, controlled, Phase 3 trial comparing
      ceftolozane/tazobactam and meropenem for treatment of
      hospital-acquired/ventilator-associated bacterial pneumonia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Baseline LRT pathogens included Klebsiella pneumoniae (34.6%),
      Pseudomonas aeruginosa (25.0%) and Escherichia coli (18.2%).
    explanation: >-
      Demonstrates that P. aeruginosa is a recovered lower-respiratory tract
      pathogen in hospital-acquired and ventilator-associated bacterial
      pneumonia.

transmission:
- name: Hospital lower-airway acquisition
  description: >-
    P. aeruginosa pneumonia is commonly acquired when hospital or ICU
    exposures place the organism into an intubated or impaired lower airway,
    especially after mechanical ventilation, reintubation, prolonged ICU care,
    or prior antibiotic selection for resistant strains.
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged
      mechanical ventilation were associated with VAP.
    explanation: >-
      Links invasive airway support and its duration to ventilator-associated
      pneumonia, the major clinical context for Pseudomonas lower-respiratory
      infection.
  - reference: PMID:41826861
    reference_title: >-
      Prevalence and phenotypic characterization of carbapenem resistance in
      multidrug-resistant Gram-negative bacteria across selected healthcare
      facilities in the United Arab Emirates: a retrospective study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: Hospitals were the primary source of MDR-CR isolates
    explanation: >-
      Supports the hospital reservoir for multidrug-resistant
      carbapenem-resistant P. aeruginosa and other Gram-negative isolates.

environmental:
- name: Mechanical ventilation and ICU airway instrumentation
  description: >-
    Endotracheal intubation, repeated airway manipulation, impaired
    mucociliary clearance, and prolonged ventilation create a hospital
    lower-airway exposure niche in which P. aeruginosa can reach the distal
    respiratory tract.
  influences_mechanisms:
  - target: Lower-Airway Pseudomonas Infection
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: >-
      Ventilation and airway instrumentation bypass upper-airway defenses and
      permit P. aeruginosa to seed the tracheobronchial tree and alveolar
      compartment.
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged
      mechanical ventilation were associated with VAP.
    explanation: >-
      Supports mechanical ventilation and reintubation as acquisition contexts
      for ventilator-associated pneumonia.

pathophysiology:
- name: Lower-Airway Pseudomonas Infection
  role: trigger
  biological_scale: TISSUE
  description: >-
    P. aeruginosa enters the distal airway or ventilated alveolar compartment
    and establishes lower-respiratory infection, bringing flagellin, type III
    secretion injectisomes, and cytotoxic effector proteins into contact with
    alveolar epithelial and innate immune cells.
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  downstream:
  - target: Airway Flagellin-TLR5 Signaling
    causal_link_type: DIRECT
    description: >-
      Flagellated bacilli are sensed by epithelial TLR5 when they contact the
      airway surface.
  - target: Type III Secretion Cytotoxicity
    causal_link_type: DIRECT
    description: >-
      Bacterial contact permits the type III secretion apparatus to inject
      Exo-family cytotoxic effectors into host cells.
  - target: NLRC4 Inflammasome IL-1 Beta Release
    causal_link_type: DIRECT
    description: >-
      Alveolar macrophages sense the type III secretion apparatus and activate
      an NLRC4 inflammasome response.
  evidence:
  - reference: PMID:35022730
    reference_title: >-
      Clinical and microbiological outcomes, by causative pathogen, in the
      ASPECT-NP randomized, controlled, Phase 3 trial comparing
      ceftolozane/tazobactam and meropenem for treatment of
      hospital-acquired/ventilator-associated bacterial pneumonia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Baseline LRT pathogens included Klebsiella pneumoniae (34.6%),
      Pseudomonas aeruginosa (25.0%) and Escherichia coli (18.2%).
    explanation: >-
      Supports the lower respiratory tract as the infected site in
      P. aeruginosa hospital-acquired and ventilator-associated pneumonia.
- name: Airway Flagellin-TLR5 Signaling
  biological_scale: CELLULAR
  description: >-
    Airway epithelial cells recognize P. aeruginosa flagellin through TLR5,
    initiating NF-kB-linked inflammatory signaling that helps launch the
    neutrophilic response to lower-airway infection.
  cell_types:
  - preferred_term: epithelial cell
    term:
      id: CL:0000066
      label: epithelial cell
  biological_processes:
  - preferred_term: toll-like receptor signaling pathway
    modifier: INCREASED
    term:
      id: GO:0002224
      label: toll-like receptor signaling pathway
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  downstream:
  - target: Neutrophilic Alveolar-Capillary Injury
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Flagellin sensing induces epithelial inflammatory mediators that converge
      with T3SS and inflammasome signals to recruit neutrophils.
  evidence:
  - reference: PMID:16239509
    reference_title: >-
      Human airway epithelial cells sense Pseudomonas aeruginosa infection via
      recognition of flagellin by Toll-like receptor 5.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: >-
      airway epithelial receptor TLR5 senses P. aeruginosa through its
      flagellin protein
    explanation: >-
      Shows that human airway epithelial cells use TLR5 to detect
      P. aeruginosa flagellin.
- name: Type III Secretion Cytotoxicity
  biological_scale: CELLULAR
  description: >-
    The P. aeruginosa type III secretion system injects ExoU, ExoS, ExoT, and
    ExoY effector proteins into contacted epithelial and innate immune cells,
    producing a cytotoxic acute-lung-injury phenotype.
  cell_types:
  - preferred_term: pulmonary alveolar type 2 cell
    term:
      id: CL:0002063
      label: pulmonary alveolar type 2 cell
  downstream:
  - target: NLRC4 Inflammasome IL-1 Beta Release
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      The type III secretion apparatus can be sensed by macrophages and
      activate an NLRC4 inflammasome response.
  - target: Neutrophilic Alveolar-Capillary Injury
    causal_link_type: DIRECT
    description: >-
      T3SS-competent organisms directly worsen epithelial cytotoxicity, alveolar
      permeability, bacterial clearance, and mortality in acute lung injury.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: >-
      the CHA strain was associated with increased in vitro cytotoxicity on
      A549 cells, as assessed by the release of lactate dehydrogenase
    explanation: >-
      A functional type III secretion system (CHA strain) produced greater
      host-cell cytotoxicity than its isogenic exsA-null mutant, supporting
      T3SS-driven cytotoxicity.
- name: NLRC4 Inflammasome IL-1 Beta Release
  biological_scale: CELLULAR
  description: >-
    Alveolar macrophages exposed to T3SS-expressing P. aeruginosa activate the
    NLRC4 inflammasome and produce IL-1 beta, an inflammatory axis that can
    impair macrophage phagocytosis and intensify lung injury.
  cell_types:
  - preferred_term: alveolar macrophage
    term:
      id: CL:0000583
      label: alveolar macrophage
  biological_processes:
  - preferred_term: interleukin-1 beta production
    modifier: INCREASED
    term:
      id: GO:0032611
      label: interleukin-1 beta production
  - preferred_term: phagocytosis
    modifier: DECREASED
    term:
      id: GO:0006909
      label: phagocytosis
  downstream:
  - target: Neutrophilic Alveolar-Capillary Injury
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Inflammasome-driven IL-1 beta release amplifies cytokine production,
      phagocytic failure, and pulmonary inflammatory damage.
  evidence:
  - reference: PMID:33489931
    reference_title: >-
      Adipose-Derived Mesenchymal Stem Cells Ameliorating Pseudomonas
      aeruginosa-induced Acute Lung Infection via Inhibition of NLRC4
      Inflammasome.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: >-
      PA infection mainly activated Nod-like receptor containing a caspase
      activating and recruitment domain 4 (NLRC4) inflammasome
    explanation: >-
      Supports NLRC4 inflammasome activation in experimental acute
      P. aeruginosa lung infection.
- name: Mucoid Alginate Biofilm Immune Evasion
  biological_scale: CELLULAR
  description: >-
    In chronic airway infection, mucoid P. aeruginosa overproduces cell-surface
    alginate and grows as biofilm, physically interfering with opsonic and
    non-opsonic macrophage phagocytosis and helping the organism persist in
    cystic-fibrosis or bronchiectatic airways.
  biological_processes:
  - preferred_term: biofilm formation
    modifier: INCREASED
    term:
      id: GO:0042710
      label: biofilm formation
  - preferred_term: phagocytosis
    modifier: DECREASED
    term:
      id: GO:0006909
      label: phagocytosis
  downstream:
  - target: Chronic Pseudomonas Airway Persistence
    causal_link_type: DIRECT
    description: >-
      Alginate-mediated antiphagocytic biofilm growth promotes persistence
      after mucoid conversion in structurally abnormal airways.
  evidence:
  - reference: PMID:37009499
    reference_title: >-
      Mechanism of resistance to phagocytosis and pulmonary persistence in
      mucoid Pseudomonas aeruginosa.
    supports: SUPPORT
    evidence_source: IN_VITRO
    quote_role: PRIMARY_RESULT
    snippet: alginate production inhibited opsonic and non-opsonic phagocytosis
    explanation: >-
      Demonstrates that bacterial surface alginate blocks human and murine
      macrophage phagocytosis of mucoid P. aeruginosa.
- name: Chronic Pseudomonas Airway Persistence
  biological_scale: TISSUE
  description: >-
    Mucoid biofilm immune evasion allows P. aeruginosa to persist in airways
    with cystic-fibrosis or bronchiectatic mucus clearance defects, converting a
    hospital-style acute Gram-negative pneumonia mechanism into a relapsing
    chronic infection pattern.
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  downstream:
  - target: Neutrophilic Alveolar-Capillary Injury
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Persistent infection repeatedly exposes the airway to Pseudomonas
      ligands, cytotoxins, and neutrophilic inflammatory injury.
  evidence:
  - reference: PMID:37009499
    reference_title: >-
      Mechanism of resistance to phagocytosis and pulmonary persistence in
      mucoid Pseudomonas aeruginosa.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: >-
      During chronic colonization of the airway and biofilm formation,
      P. aeruginosa converts to a mucoid phenotype
    explanation: >-
      The study's introduction restates the established clinical natural
      history of chronic P. aeruginosa airway colonization, in which the
      organism converts to a mucoid phenotype.
- name: Neutrophilic Alveolar-Capillary Injury
  biological_scale: TISSUE
  description: >-
    Epithelial TLR5 signaling, macrophage NLRC4/IL-1 beta activation, and T3SS
    cytotoxicity converge on a neutrophilic inflammatory exudate that injures
    the alveolar-capillary barrier, causes protein-rich edema, and can progress
    to acute respiratory failure, sepsis, and death.
  cell_types:
  - preferred_term: neutrophil
    term:
      id: CL:0000775
      label: neutrophil
  locations:
  - preferred_term: alveolus of lung
    term:
      id: UBERON:0002299
      label: alveolus of lung
  biological_processes:
  - preferred_term: inflammatory response
    modifier: INCREASED
    term:
      id: GO:0006954
      label: inflammatory response
  downstream:
  - target: Dyspnea
    causal_link_type: DIRECT
    description: >-
      Alveolar-capillary barrier failure and protein-rich edema impair gas
      exchange, producing dyspnea.
  - target: Acute respiratory distress syndrome
    causal_link_type: DIRECT
    description: >-
      Diffuse neutrophilic alveolar injury and permeability edema can progress
      to acute respiratory distress syndrome physiology.
  - target: Sepsis
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Severe lower-respiratory injury with invasive infection can disseminate
      or drive a systemic inflammatory response, causing sepsis.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: >-
      increased lung injury, as assessed by the wet/dry weight ratio for the
      lungs and the protein level in bronchoalveolar lavage fluid
    explanation: >-
      Supports edema and alveolar protein leak as readouts of T3SS-amplified
      acute lung injury in a P. aeruginosa pneumonia model.

phenotypes:
- name: Fever
  phenotype_term:
    preferred_term: Fever
    term:
      id: HP:0001945
      label: Fever
  frequency: Common
  description: >-
    Fever is part of the acquired inflammatory pneumonia syndrome caused by
    P. aeruginosa.
  evidence:
  - reference: PMID:42807670
    reference_title: >-
      High-Dose Inhaled Colistin-Aminoglycoside Combination Therapy in
      Critically Ill Patients With Multidrug-Resistant Pseudomonas aeruginosa
      Hospital/Ventilator-Associated Pneumonia: A Case Report and Literature
      Review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      he developed fever, copious purulent secretions, and acute respiratory
      failure requiring ICU admission and MV.
    explanation: >-
      Documents fever in a critically ill patient with multidrug-resistant
      P. aeruginosa ventilator-associated pneumonia.
- name: Purulent tracheal secretions
  phenotype_term:
    preferred_term: Purulent tracheal secretions
    term:
      id: HP:0032016
      label: Abnormal sputum
  frequency: Common
  description: >-
    Purulent tracheal/airway secretions are a diagnostic hallmark of
    ventilator-associated P. aeruginosa and other Gram-negative pneumonias.
  evidence:
  - reference: PMID:35022730
    reference_title: >-
      Clinical and microbiological outcomes, by causative pathogen, in the
      ASPECT-NP randomized, controlled, Phase 3 trial comparing
      ceftolozane/tazobactam and meropenem for treatment of
      hospital-acquired/ventilator-associated bacterial pneumonia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      purulent tracheal secretions with ≥1 other clinical criterion
    explanation: >-
      Purulent tracheal secretions are a required diagnostic criterion for
      ventilated HAP/VAP in the ASPECT-NP trial population.
- name: Dyspnea
  phenotype_term:
    preferred_term: Dyspnea
    term:
      id: HP:0002094
      label: Dyspnea
  frequency: Common
  severity: Moderate to severe
  description: >-
    Lower-airway infection and alveolar injury impair gas exchange, producing
    dyspnea that can worsen into respiratory failure in severe ICU disease.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: >-
      increased lung injury, as assessed by the wet/dry weight ratio for the
      lungs and the protein level in bronchoalveolar lavage fluid
    explanation: >-
      Supports alveolar permeability injury as the physiologic basis for
      respiratory compromise in T3SS-positive P. aeruginosa pneumonia; the
      inference from the rat model to human dyspnea is indirect.
  - reference: PMID:42807670
    reference_title: >-
      High-Dose Inhaled Colistin-Aminoglycoside Combination Therapy in
      Critically Ill Patients With Multidrug-Resistant Pseudomonas aeruginosa
      Hospital/Ventilator-Associated Pneumonia: A Case Report and Literature
      Review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      he developed fever, copious purulent secretions, and acute respiratory
      failure requiring ICU admission and MV.
    explanation: >-
      Documents acute respiratory failure in a human patient with
      P. aeruginosa ventilator-associated pneumonia.
- name: Increased total leukocyte count
  phenotype_term:
    preferred_term: Increased total leukocyte count
    term:
      id: HP:0001974
      label: Increased total leukocyte count
  frequency: Common
  description: >-
    Leukocytosis accompanies the systemic inflammatory response to
    ventilator-associated Pseudomonas and other Gram-negative pneumonias.
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Reintubation, elevated CRP, leukocytosis, hypercapnia, and prolonged
      mechanical ventilation were associated with VAP.
    explanation: >-
      Supports leukocytosis as a clinical correlate of
      ventilator-associated pneumonia.
- name: Elevated circulating C-reactive protein concentration
  phenotype_term:
    preferred_term: Elevated circulating C-reactive protein concentration
    term:
      id: HP:0011227
      label: Elevated circulating C-reactive protein concentration
  frequency: Common
  description: >-
    CRP rises as part of the acute inflammatory response to
    ventilator-associated Gram-negative pneumonia.
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: CRP demonstrated good-to-moderate discriminative ability for VAP
    explanation: >-
      Supports elevated CRP as an inflammatory marker used to discriminate
      ventilator-associated pneumonia.
- name: Acute respiratory distress syndrome
  phenotype_term:
    preferred_term: Acute respiratory distress syndrome
    term:
      id: HP:0033677
      label: Acute respiratory distress syndrome
  frequency: Subset
  severity: Severe
  description: >-
    Severe T3SS-driven alveolar-capillary injury can progress to acute lung
    injury and ARDS physiology.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: >-
      increased lung injury, as assessed by the wet/dry weight ratio for the
      lungs and the protein level in bronchoalveolar lavage fluid
    explanation: >-
      Supports the Pseudomonas T3SS as a driver of permeability-type acute lung
      injury, the experimental counterpart of severe ARDS progression; the
      inference from the rat model to human ARDS is indirect.
  - reference: PMID:42807670
    reference_title: >-
      High-Dose Inhaled Colistin-Aminoglycoside Combination Therapy in
      Critically Ill Patients With Multidrug-Resistant Pseudomonas aeruginosa
      Hospital/Ventilator-Associated Pneumonia: A Case Report and Literature
      Review.
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      he developed fever, copious purulent secretions, and acute respiratory
      failure requiring ICU admission and MV.
    explanation: >-
      Documents acute respiratory failure requiring mechanical ventilation in a
      human patient with P. aeruginosa pneumonia, the severe respiratory
      endpoint of which ARDS is the most severe form.
- name: Sepsis
  phenotype_term:
    preferred_term: Sepsis
    term:
      id: HP:0100806
      label: Sepsis
  frequency: Subset
  severity: Severe
  description: >-
    Invasive lower-respiratory P. aeruginosa infection can disseminate or
    trigger systemic inflammation, causing sepsis or septic shock.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: >-
      more likely to develop bacteremia, septic shock, and multiple organ
      failure
    explanation: >-
      The study's introduction restates the human clinical observation that
      ventilator-acquired P. aeruginosa pneumonia frequently progresses to
      bacteremia and septic shock.

prevalence:
- population: Mechanically ventilated patients, Tuzla tertiary-care ICU
  measure_type: PERIOD_PREVALENCE
  notes: >-
    VAP occurred in 34.7% of mechanically ventilated patients in this cohort,
    with Gram-negative pathogens predominating and P. aeruginosa the
    second-ranked causative pathogen. This is overall VAP occurrence in the
    ventilated cohort, not P. aeruginosa-specific disease prevalence, so no
    disease-specific rate is asserted in the structured slots.
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: VAP was diagnosed in 41 patients (34.7%).
    explanation: >-
      Reports the proportion of mechanically ventilated patients who developed
      VAP in a cohort where P. aeruginosa was the second-ranked pathogen.

diagnosis:
- name: Lower-respiratory culture with antimicrobial susceptibility testing
  description: >-
    Pseudomonas pneumonia is confirmed by culturing lower-respiratory samples,
    such as endotracheal aspirate or bronchoalveolar lavage fluid, and testing
    antimicrobial susceptibility because MDR and carbapenem-resistant isolates
    are common in hospital-acquired disease.
  evidence:
  - reference: PMID:42801252
    reference_title: >-
      Common Organisms and Their Drug Resistance Patterns in Endotracheal
      Aspirate Samples of Patients With Ventilator-Associated Pneumonia: A
      Retrospective Observational Study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Endotracheal aspirate samples were cultured, and antimicrobial
      susceptibility testing was performed
    explanation: >-
      Supports endotracheal aspirate culture followed by antimicrobial
      susceptibility testing in patients with ventilator-associated pneumonia.
  - reference: PMID:41826861
    reference_title: >-
      Prevalence and phenotypic characterization of carbapenem resistance in
      multidrug-resistant Gram-negative bacteria across selected healthcare
      facilities in the United Arab Emirates: a retrospective study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      period prevalence calculated within total isolates of each organism group
      was highest for MDR-CR Acinetobacter (22.8%), followed by MDR-CR P.
      aeruginosa (12.9%)
    explanation: >-
      Supports that multidrug-resistant, carbapenem-resistant P. aeruginosa
      isolates are common, motivating antimicrobial susceptibility testing; the
      figure is a resistance proportion among isolates, not disease prevalence.
- name: CRP and leukocyte inflammatory-marker support
  description: >-
    Elevated CRP and leukocytosis support the clinical diagnosis and risk
    assessment of ventilator-associated pneumonia but do not identify
    P. aeruginosa without microbiology.
  markers: C-reactive protein; leukocyte count
  evidence:
  - reference: PMID:42592972
    reference_title: >-
      Risk factors and microbiological profile of ventilator-associated
      pneumonia in a tertiary-care intensive care unit in Tuzla: a prospective
      observational study.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: CRP demonstrated good-to-moderate discriminative ability for VAP
    explanation: >-
      Supports CRP as a discriminating inflammatory biomarker for VAP in an ICU
      cohort.

treatments:
- name: Susceptibility-guided antipseudomonal beta-lactam therapy
  description: >-
    Ventilated hospital-acquired or ventilator-associated P. aeruginosa
    pneumonia is treated with an antipseudomonal antibiotic regimen guided by
    isolate susceptibility, local resistance, severity, and renal function; the
    ASPECT-NP trial compared ceftolozane/tazobactam with meropenem in a
    Gram-negative HAP/VAP population that included P. aeruginosa.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Antibiotic Therapy
    term:
      id: NCIT:C15620
      label: Antibiotic Therapy
    therapeutic_agent:
    - preferred_term: ceftolozane
      term:
        id: CHEBI:134719
        label: ceftolozane
    - preferred_term: tazobactam
      term:
        id: CHEBI:9421
        label: tazobactam
    - preferred_term: meropenem
      term:
        id: CHEBI:43968
        label: meropenem
  target_mechanisms:
  - target: Lower-Airway Pseudomonas Infection
    treatment_effect: INHIBITS
    description: >-
      Active antipseudomonal therapy kills or suppresses the lower-respiratory
      P. aeruginosa population driving pneumonia.
  - target: Neutrophilic Alveolar-Capillary Injury
    treatment_effect: INHIBITS
    description: >-
      Bacterial clearance removes the trigger for ongoing neutrophilic alveolar
      barrier injury.
  evidence:
  - reference: PMID:35022730
    reference_title: >-
      Clinical and microbiological outcomes, by causative pathogen, in the
      ASPECT-NP randomized, controlled, Phase 3 trial comparing
      ceftolozane/tazobactam and meropenem for treatment of
      hospital-acquired/ventilator-associated bacterial pneumonia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      Mechanically ventilated participants with
      hospital-acquired/ventilator-associated bacterial pneumonia were
      randomized
    explanation: >-
      Supports randomized treatment of ventilated HAP/VAP with
      ceftolozane/tazobactam or meropenem, a trial population in which
      P. aeruginosa was a common baseline lower-respiratory pathogen.
- name: Adjunctive inhaled colistin-aminoglycoside therapy for selected MDR cases
  description: >-
    Critically ill patients with MDR P. aeruginosa HAP/VAP may receive inhaled
    colistin followed by an inhaled aminoglycoside as adjunctive local therapy
    on top of systemic antibiotics when conventional systemic options are
    limited, but this remains a selected-case MDR strategy rather than a
    universal first-line regimen.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Antibiotic Therapy
    term:
      id: NCIT:C15620
      label: Antibiotic Therapy
    therapeutic_agent:
    - preferred_term: colistin
      term:
        id: CHEBI:37943
        label: colistin
    - preferred_term: amikacin
      term:
        id: CHEBI:2637
        label: amikacin
    - preferred_term: tobramycin
      term:
        id: CHEBI:28864
        label: tobramycin
  target_mechanisms:
  - target: Lower-Airway Pseudomonas Infection
    treatment_effect: INHIBITS
    description: >-
      Nebulized polymyxin and aminoglycoside delivery attempts to achieve high
      intrapulmonary concentrations against MDR organisms in the infected lung.
  evidence:
  - reference: PMID:42807670
    reference_title: >-
      High-Dose Inhaled Colistin-Aminoglycoside Combination Therapy in
      Critically Ill Patients With Multidrug-Resistant Pseudomonas aeruginosa
      Hospital/Ventilator-Associated Pneumonia: A Case Report and Literature
      Review.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: We describe three critically ill patients with HAP/VAP due to MDR PA.
    explanation: >-
      Documents adjunctive inhaled colistin plus amikacin or tobramycin in
      critically ill MDR P. aeruginosa HAP/VAP cases.

progression:
- phase: Acute ventilator-associated pneumonia
  notes: >-
    Acute lower-airway P. aeruginosa infection in a ventilated or impaired
    airway drives flagellin- and T3SS-mediated neutrophilic pneumonia that can
    progress to alveolar-capillary barrier failure, respiratory failure, and
    sepsis.
  evidence:
  - reference: PMID:35022730
    reference_title: >-
      Clinical and microbiological outcomes, by causative pathogen, in the
      ASPECT-NP randomized, controlled, Phase 3 trial comparing
      ceftolozane/tazobactam and meropenem for treatment of
      hospital-acquired/ventilator-associated bacterial pneumonia.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      purulent tracheal secretions with ≥1 other clinical criterion
    explanation: >-
      Defines the acute ventilated-pneumonia presentation in the trial
      population.
- phase: Chronic mucoid airway infection
  notes: >-
    In structurally abnormal airways (cystic fibrosis, bronchiectasis),
    P. aeruginosa converts to a mucoid alginate-overproducing phenotype and
    establishes a relapsing, phagocytosis-resistant chronic airway infection.
  evidence:
  - reference: PMID:37009499
    reference_title: >-
      Mechanism of resistance to phagocytosis and pulmonary persistence in
      mucoid Pseudomonas aeruginosa.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: >-
      During chronic colonization of the airway and biofilm formation,
      P. aeruginosa converts to a mucoid phenotype
    explanation: >-
      Describes the chronic mucoid-conversion phase of P. aeruginosa airway
      infection.

clinical_trials:
- name: NCT02070757
  phase: PHASE_III
  status: COMPLETED
  description: >-
    ASPECT-NP: a Phase 3 randomized, double-blind trial comparing intravenous
    ceftolozane/tazobactam with meropenem in adults with ventilated
    hospital-acquired or ventilator-associated bacterial pneumonia.
  evidence:
  - reference: clinicaltrials:NCT02070757
    reference_title: "A Prospective, Randomized, Double-Blind, Multicenter, Phase 3 Study to Assess the Safety and Efficacy of Intravenous Ceftolozane/Tazobactam Compared With Meropenem in Adult Patients With Ventilated Nosocomial Pneumonia"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: >-
      This is a phase 3, multicenter, prospective, randomized study of
      intravenous (IV) ceftolozane/tazobactam versus IV meropenem in the
      treatment of adult participants with either ventilator-associated
      bacterial pneumonia (VABP) or ventilated hospital-acquired bacterial
      pneumonia (HABP).
    explanation: >-
      Establishes the ASPECT-NP trial of ceftolozane/tazobactam versus
      meropenem for ventilated nosocomial pneumonia.

animal_models:
- name: T3SS-competent rat acute lung injury model
  species: Rattus norvegicus
  genotype: Wild type
  publication: PMID:15972518
  description: >-
    Rats challenged intratracheally with a T3SS-competent P. aeruginosa CHA
    strain developed greater alveolar permeability injury, impaired bacterial
    clearance, and higher mortality than rats challenged with the isogenic
    exsA-null CHA-D1 strain, directly testing T3SS contribution to acute
    Pseudomonas lung injury.
  associated_phenotypes:
  - Pseudomonas acute lung injury
  - Elevated bronchoalveolar lavage protein
  - Increased lung wet/dry weight ratio
  modeled_mechanisms:
  - target: Type III Secretion Cytotoxicity
    relationship: RECAPITULATES
    fidelity: HIGH
    model_scale: TISSUE
    description: >-
      Comparing a wild-type T3SS strain to an exsA-null mutant isolates the
      type III secretion contribution to alveolar permeability injury.
    evidence:
    - reference: PMID:15972518
      reference_title: >-
        Alveolar response to Pseudomonas aeruginosa: role of the type III
        secretion system.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: >-
        increased lung injury, as assessed by the wet/dry weight ratio for the
        lungs and the protein level in bronchoalveolar lavage fluid
      explanation: >-
        Shows that the T3SS-competent challenge produced more permeability
        edema than the T3SS-deficient mutant.
  evidence:
  - reference: PMID:15972518
    reference_title: >-
      Alveolar response to Pseudomonas aeruginosa: role of the type III
      secretion system.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: >-
      decreased bacterial clearance from the lungs, ultimately leading to an
      increased mortality rate
    explanation: >-
      Supports bacterial-clearance and mortality phenotypes in the
      T3SS-competent rat acute lung injury model.

review_notes: >-
  Duplicate preflight found no exact MONDO:0037398 or exact-label local entry
  in ignored-inclusive searches and no all-state GitHub PR or issue carrying
  the same MONDO identifier before this entry was seeded. Curation retained the
  OpenScientist report's TLR5, T3SS, NLRC4, alginate, VAP, and treatment
  mechanisms. The purulent-secretions concept is kept as a phenotype bound to
  HP:0032016 (Abnormal sputum) after the report's own CURIE was rejected as
  incorrect; the report's pulmonary-consolidation binding remains unused, and
  host CFTR genetics are scoped as a structural airway susceptibility context
  rather than a Mendelian cause. Prevention (ventilator-care bundles, subglottic
  secretion drainage, antimicrobial stewardship) is out of scope because dismech
  has no prevention section.
📚

References & Deep Research

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

OpenScientist ▸
Pneumonia Caused By *Pseudomonas aeruginosa* Infection — Comprehensive Disease Report
openscientist-autonomous 49 citations 2026-09-30T02:21:20.271868

Pneumonia Caused By Pseudomonas aeruginosa Infection — Comprehensive Disease Report

Target disease: Pneumonia Caused By Pseudomonas aeruginosa Infection MONDO ID: MONDO:0037398 · Category: Infectious Disease Pathogen taxon: Pseudomonas aeruginosa — NCBI:txid287 (species); genus Pseudomonas NCBI:txid286 Investigation: 5 iterations · 9 confirmed findings · 61 papers reviewed · Report date 2026-09-30

Summary

Pneumonia caused by Pseudomonas aeruginosa is an opportunistic Gram-negative lower-respiratory-tract infection that predominantly afflicts hosts with compromised mechanical or immune barriers — mechanically ventilated ICU patients, neutropenic and immunocompromised patients, and people with structural lung disease such as cystic fibrosis (CF) and bronchiectasis. It is not a heritable Mendelian disorder; its "etiology" is infectious, with host genetics (most paradigmatically CFTR mutations) acting as susceptibility modifiers rather than causes. Clinically it is one of the leading causes of hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), and it is increasingly multidrug-resistant (MDR) and carbapenem-resistant (CRPA) — a WHO critical-priority pathogen.

The pathophysiology splits into two mechanistic branches. In acute pneumonia, the Type III Secretion System (T3SS) injects cytotoxic effectors (ExoU, ExoS, ExoT, ExoY) into host cells, while flagellin is sensed by TLR5 on airway epithelium and the T3SS is sensed by the NLRC4 inflammasome in alveolar macrophages, driving IL-1β-mediated neutrophilic inflammation, alveolar–capillary barrier destruction, acute lung injury/ARDS and, frequently, death. In chronic pneumonia (the CF/bronchiectasis paradigm), conversion to a mucoid, alginate-overproducing biofilm phenotype evades opsonic and non-opsonic phagocytosis and establishes lifelong airway persistence with progressive lung-function decline.

Prognosis is dominated by two modifiable factors — antimicrobial resistance and inappropriate initial empiric therapy — both of which sharply raise mortality. VAP attributable mortality is roughly 30%, and 28-day all-cause mortality in ventilated HAP/VAP trials remains ~20–26%. First-line management uses anti-pseudomonal β-lactams; ceftolozane/tazobactam was non-inferior to meropenem in the phase 3 ASPECT-NP trial. Prevention rests on ventilator-care bundles (with several traditional components now questioned), and emerging therapies include inhaled antibiotics, anti-virulence monoclonal antibodies, DNA vaccines, and bacteriophage therapy.

1. Disease Information

Overview. Pseudomonas aeruginosa pneumonia is a lung parenchymal infection caused by the ubiquitous, aerobic, non-fermenting Gram-negative bacillus P. aeruginosa. It occurs mainly as hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP), and as chronic airway infection in structural lung disease. Acute P. aeruginosa pneumonia predominantly affects immunocompromised, neutropenic, and mechanically ventilated patients (PMID: 25520826, PMID: 9570172).

Key identifiers. - MONDO: MONDO:0037398 - Causative organism — NCBI Taxonomy: Pseudomonas aeruginosa, txid287 - ICD-10: J15.1 (Pneumonia due to Pseudomonas); ICD-11: bacterial pneumonia with Pseudomonas as the causal agent - MeSH: "Pneumonia, Bacterial" + "Pseudomonas Infections" / "Pseudomonas aeruginosa" - OMIM/Orphanet: Not applicable as a Mendelian entity (infectious disease); CFTR/cystic fibrosis (OMIM 219700; Orphanet ORPHA:586) is the relevant host-susceptibility entry.

Synonyms / alternative names. Pseudomonas pneumonia; Pseudomonal pneumonia; P. aeruginosa lower respiratory tract infection; Pseudomonas aeruginosa HAP/VAP; nosocomial Pseudomonas pneumonia.

Data source type. This report aggregates disease-level resources (surveillance cohorts, randomized trials, mechanistic model-organism and in-vitro studies, and registry data) rather than individual EHR-derived patient records.

2. Etiology

Primary cause (infectious). The disease is caused by infection with P. aeruginosa. It is fundamentally an opportunistic infection: host predisposition defines who develops disease.

Risk factors (environmental / host). - Mechanical ventilation / endotracheal intubation — the dominant risk setting; VAP incidence is ~7–15% of ventilated patients (PMID: 30390751), and prolonged ventilation, reintubation and elevated CRP associate with VAP (PMID: 42592972). - Immunocompromise / neutropenia — P. aeruginosa was the most frequent organism in bacteremic pneumonia in neutropenic cancer patients (PMID: 9570172). - Structural lung disease — cystic fibrosis and bronchiectasis (chronic branch). - Prior antibiotic exposure — drives resistant strains and inappropriate initial therapy; associated with higher mortality (51.3% vs 34.0%, p<0.001) in Gram-negative severe sepsis (PMID: 21499086). - Comorbidities — diabetes (independently associated with MDR infection, adjusted OR 2.82), cardiovascular disease, COPD, hypertension (PMID: 42393552); ECMO support (PMID: 42685911); chest trauma with high injury-severity score and tracheostomy (PMID: 41978407).

Genetic (host susceptibility) risk factors. - CFTR mutations (cystic fibrosis). The paradigmatic host genetic risk factor for chronic pulmonary P. aeruginosa infection. CF produces progressive lung disease with chronic infection, mucus accumulation, airway inflammation and structural damage, with P. aeruginosa as a dominant chronic pathogen (PMID: 38702073, PMID: 41010996). The most common allele is F508del (PMID: 38742380). - Inflammasome variants. Gain-of-function variants in NLRP3/NLRC4 inflammasome genes have been associated with clinical outcomes in CF (PMID: 33848452).

Protective factors. No validated protective genetic variant is established for this infectious disease. Environmental/behavioral protection is essentially prevention of acquisition (see §13): avoiding intubation, minimizing sedation, early extubation and mobilization (PMID: 31585480). Innate effectors such as Cmpk2 enhance neutrophil phagocytosis and host survival (model-organism evidence; PMID: 40616692).

Gene–environment interactions. The clearest interaction is CFTR deficiency × environmental P. aeruginosa exposure → chronic mucoid airway infection. Prior-antibiotic environment × bacterial resistance genotype → inappropriate therapy → death is a second, treatment-relevant interaction.

3. Phenotypes

P. aeruginosa pneumonia presents as a bacterial pneumonia syndrome; phenotypes are acquired clinical manifestations, not congenital.

Phenotype Type Onset Severity / course Frequency Suggested HPO
Fever Clinical sign Adult-onset (acquired) Variable Common HP:0001945
Cough / productive cough Symptom Acquired Variable Common HP:0012735
Dyspnea Symptom Acquired, acute/subacute Moderate–severe Common HP:0002094
Hypoxemia / respiratory failure Lab/physiologic Acute Severe Frequent in ICU HP:0012418 / HP:0002878
Purulent sputum / tracheal secretions Sign Acquired Variable Common (VAP) HP:0025440
Leukocytosis Lab abnormality Acute Variable Common HP:0001974
Elevated CRP Lab abnormality Acute Marker of burden (AUC 0.83 for VAP) Common (PMID: 42592972) HP:0011227
Bacteremia / sepsis / septic shock Complication Acute Severe, high-mortality Subset (poor outcome) HP:0031273 / HP:0100806
Pulmonary infiltrates / consolidation Imaging sign Acute Variable Diagnostic HP:0031977
ARDS / acute lung injury Physiologic Acute Severe T3SS-driven subset HP:0033677

Quality-of-life impact. Acute P. aeruginosa pneumonia in ventilated patients prolongs mechanical ventilation (12.5 vs 7.3 days) and hospitalization (19.6 vs 12.2 days) (PMID: 42592972). In the chronic CF branch, persistent infection drives progressive lung-function decline, exacerbations, and reduced survival (PMID: 38702073).

4. Genetic / Molecular Information

No human causal gene produces P. aeruginosa pneumonia — it is infectious. Genetics operates on two axes:

(a) Host susceptibility / modifier genes (human). - CFTR (HGNC:1884; OMIM 602421) — loss-of-function mutations (F508del most common) cause CF and predispose to chronic P. aeruginosa airway infection (PMID: 38742380, PMID: 42774065). Variant classes include in-frame deletion (F508del), nonsense/stop-codon, splice, and gating variants; population-specific alleles (e.g., N1303K, G542X, 2789+5G>A enriched in Italy) exist (PMID: 42370441). - NLRP3 / NLRC4 — inflammasome gain-of-function variants associated with CF outcomes (PMID: 33848452). - TLR5, MUC1 — innate-sensing genes that modulate epithelial responses (PMID: 16239509, PMID: 22250084).

(b) Bacterial virulence & resistance loci (pathogen genome). - T3SS effector genes: exoU (phospholipase A2, most cytotoxic), exoS (ADP-ribosyltransferase + GAP), exoT (GAP), exoY (nucleotidyl cyclase); master regulator exsA (PMID: 25520826, PMID: 15972518). - Alginate biosynthesis: algD operon, regulator mucA (mucoid conversion) (PMID: 37009499). - Flagellin: fliC (TLR5 ligand) (PMID: 16239509). - Resistance determinants: carbapenemase and other AMR genes confirmed by whole-genome sequencing in high-risk clones (PMID: 41751514).

Epigenetics / chromosomal abnormalities: Not applicable to the disease as an infectious entity in humans.

5. Environmental Information

Infectious agent. Pseudomonas aeruginosa (NCBI txid287), an aerobic, motile, non-fermenting Gram-negative bacillus. It is environmentally ubiquitous (water, moist surfaces, hospital reservoirs, medical devices) and forms biofilms on ventilator circuits and endotracheal tubes.

Environmental / occupational factors. Hospital and ICU environments, contaminated respiratory equipment, and indwelling devices are the principal reservoirs; >90% of MDR carbapenem-resistant P. aeruginosa isolates in one large UAE survey originated in hospitals (PMID: 41826861).

Lifestyle factors. Not the primary drivers; smoking/COPD contribute to structural lung disease that raises susceptibility (PMID: 42393552).

6. Mechanism / Pathophysiology

Ordered causal chain

ACUTE CYTOTOXIC BRANCH (ventilated / immunocompromised host):

  1. P. aeruginosa colonizes the lower airway (aided by ventilation, impaired clearance) → leads to contact with alveolar epithelium and macrophages.
  2. Bacterial flagellin is recognized by TLR5 on the apical surface of airway epithelial cells → results in NF-κB activation and pro-inflammatory chemokine/cytokine transcription (PMID: 16239509). (MUC1 tethers to TLR5 and dampens this signal — a counter-regulatory branch; PMID: 22250084.)
  3. The Type III Secretion System injects effectors ExoU/ExoS/ExoT/ExoY into host cells → causes direct cytotoxicity; ExoU (phospholipase A2) is most cytotoxic and induces mitochondrial damage in macrophages (PMID: 35130452).
  4. Alveolar macrophages detect the T3SS → activate the NLRC4 inflammasome → caspase-1 → IL-1β/IL-1α release (PMID: 42779855). NLRC4 activation also attenuates macrophage phagocytosis, worsening bacterial persistence (inferred causal link from model organism; PMID: 33489931).
  5. IL-1β-driven inflammation → massive neutrophil recruitment and alveolar–capillary barrier disruption → increased permeability, pulmonary edema, protein-rich BALF (demonstrated as ↑wet/dry ratio and ↑BALF protein in the T3SS-competent CHA strain vs exsA-null mutant) (PMID: 15972518).
  6. → Acute lung injury / ARDS, hypoxemic respiratory failure, sepsis/septic shock → death in a substantial fraction.

CHRONIC PERSISTENCE BRANCH (CF / bronchiectasis host):

  1. Impaired mucociliary clearance (e.g., CFTR loss) → chronic airway colonization.
  2. mucA mutation → alginate overproduction → conversion to mucoid biofilm phenotype.
  3. Alginate inhibits opsonic and non-opsonic phagocytosis by human (THP-1) and murine (MH-S) macrophages, blocking CD11b/CD14 receptor–ligand interactions (PMID: 37009499).
  4. → immune evasion, chronic persistent infection, antibiotic tolerance → recurrent exacerbations, progressive lung-function decline, mortality (PMID: 38702073).
            P. aeruginosa in lower airway
                       |
     ┌─────────────────┴──────────────────┐
     ACUTE (T3SS+ / planktonic)          CHRONIC (mucoid / biofilm)
     |                                     |
   flagellin→TLR5→NF-κB (epi)          mucA → alginate overproduction
   T3SS→ExoU/S/T/Y (cytotoxic)         → blocks CD11b/CD14 phagocytosis
   T3SS→NLRC4 inflammasome→IL-1β        → immune evasion
     |                                     |
   neutrophil influx + barrier loss     chronic persistence, tolerance
     |                                     |
   ALI / ARDS / respiratory failure     progressive lung decline
     |                                     |
high acute mortality            recurrent exacerbations, ↓survival

Cell types & GO/CL terms. Alveolar epithelial cells (CL:0000066; type II CL:0002063), alveolar macrophages (CL:0000583), neutrophils (CL:0000775). Biological processes: T3SS-dependent cytotoxicity, inflammasome complex assembly (GO:0140738), NLRC4 inflammasome activation, IL-1β production (GO:0032611), TLR5 signaling (GO:0034146), neutrophil chemotaxis (GO:0030593), phagocytosis (GO:0006909). Subcellular: mitochondrion (GO:0005739) (ExoU damage), plasma membrane, extracellular alginate matrix.

Molecular profiling. Multi-omics of acute P. aeruginosa infection and mitochondrial gene-expression analysis of ARDS datasets (GEO) identified Cmpk2 as an innate-immune protective node enriched in neutrophils by scRNA-seq (PMID: 40616692, PMID: 40216004).

7. Anatomical Structures Affected

  • Primary organ: Lung (UBERON:0002048), lung parenchyma / alveoli (alveolus UBERON:0002299), respiratory system (UBERON:0001004).
  • Secondary involvement: Bloodstream (bacteremia/sepsis), systemic multi-organ dysfunction in septic shock; ARDS affects the alveolar–capillary unit bilaterally.
  • Tissues: Airway and alveolar epithelium (apical surface where TLR5 is expressed on human tracheal epithelium; PMID: 16239509); pulmonary capillary endothelium; alveolar interstitium.
  • Cells (CL): alveolar macrophages (CL:0000583), neutrophils (CL:0000775), alveolar type I/II epithelial cells (CL:0002062 / CL:0002063).
  • Subcellular (GO CC): mitochondrion (GO:0005739), plasma membrane, cytosolic inflammasome.
  • Localization / lateralization: Typically bilateral in VAP/ARDS; may be unilateral/multilobar in focal bronchopneumonia.

8. Temporal Development

  • Onset (acute branch): Acute to subacute, developing over hours–days; VAP is defined as pneumonia arising >48 h after intubation, with early-onset (~58%) and late-onset (~42%) forms (PMID: 41939663).
  • Onset (chronic branch): Insidious, beginning in childhood in CF and progressing over decades (PMID: 38702073).
  • Progression: Acute disease can progress rapidly to ARDS, septic shock and death; the chronic branch follows a relapsing–remitting course of exacerbations superimposed on progressive decline.
  • Duration: Acute pneumonia is treated over days–weeks; chronic P. aeruginosa airway infection is typically lifelong once mucoid biofilm is established.
  • Remission: Acute disease can resolve with appropriate, timely antimicrobial therapy; chronic mucoid infection rarely eradicates. Critical intervention window: early appropriate empiric therapy (see §11) is the key modifiable determinant of outcome.

9. Inheritance and Population (Epidemiology)

Inheritance: Not applicable (infectious disease). Host susceptibility via CFTR is autosomal recessive.

Epidemiology (frequency as HAP/VAP pathogen).

Setting / cohort P. aeruginosa rank / frequency Resistance PMID
Chinese HAP, 37 hospitals (n=543) 3rd, 13.73% (behind A. baumannii 24.89%, K. pneumoniae 21.57%); HAP mortality 15.8% — 41758741
Egyptian ICU VAP (n=120) 47/120 (39.2%) 85.1% MDR; 80% colistin-S, only 12.5% CAZ/AVI-S 41877050
Saudi HA-GNB, 5-yr (n=377) 2nd, 34.0% meropenem-R 34.3%; ciprofloxacin-R 44.4% 42393552
UAE MDR-CRO surveillance MDR-CR P. aeruginosa period prevalence 12.9% carbapenem-resistant 41826861
Bosnian ICU VAP (n=118) 2nd after A. baumannii; VAP 34.7% Gram-neg ≈85% 42592972

Chronic CF branch: chronic P. aeruginosa infection affects ~30–37% of adults and ~5–7% of paediatric CF patients in the Italian CF Registry, declining with CFTR-modulator therapy (PMID: 38742380, PMID: 42370441).

Geographic distribution: Global; MDR/CRPA burden is rising, with regional variation and WHO critical-priority status (PMID: 42523687). Sex/age: Reflects the underlying ICU/comorbid population (older adults, male predominance in several cohorts).

10. Diagnostics

Clinical/lab tests. - Microbiology (gold standard): culture of respiratory specimens — endotracheal aspirate (ETA) or bronchoalveolar lavage (BAL), with semi-quantitative thresholds (≥10⁵ CFU/mL for ETA) (PMID: 41939663, PMID: 42801252). Antimicrobial susceptibility testing (CLSI) is essential given high MDR rates. - Inflammatory markers / biomarkers: CRP discriminates VAP (AUC 0.83; PMID: 42592972); leukocytosis; bronchoalveolar IL-1β correlates with bacterial burden and may mark ongoing/unresolved infection (PMID: 12626989). - Molecular/genomic: whole-genome sequencing profiles resistance and virulence (PMID: 41751514); metagenomic next-generation sequencing aids complex cases (PMID: 42661655). - Imaging: chest radiograph/CT showing infiltrates/consolidation (used with clinical criteria).

Clinical criteria. Modified Clinical Pulmonary Infection Score (CPIS >6), CDC/NHSN surveillance definitions for HAP/VAP; VAP requires pneumonia >48 h post-intubation (PMID: 41939663, PMID: 42393552).

Differential diagnosis. Other Gram-negative HAP/VAP pathogens (A. baumannii, K. pneumoniae), S. aureus pneumonia, aspiration pneumonitis, ARDS of non-infectious cause, pulmonary aspergillosis in the immunocompromised.

Genetic testing. Not for the infection itself; CFTR sequencing / sweat chloride testing is indicated when chronic P. aeruginosa infection suggests undiagnosed CF (diagnostic delay causes irreversible damage; PMID: 42774065).

11. Outcome / Prognosis

Mortality. - VAP attributable mortality ~30% (PMID: 18060758). - 28-day all-cause mortality in ventilated HAP/VAP (ASPECT-NP, Gram-negative pathogens): 20.1% (ceftolozane/tazobactam) vs 25.8% (meropenem) (PMID: 35022730); ~23.7–24.0% with severe respiratory failure (PMID: 36773112). - Overall HA-GNB in-hospital mortality up to ~40% in high-comorbidity cohorts (PMID: 42393552).

Dominant prognostic factors (modifiable). 1. Carbapenem/multidrug resistance — CR infections carry significantly higher mortality across pathogens including P. aeruginosa (multicentre Indian surveillance, 159,336 patients; PMID: 42707186). 2. Inappropriate initial therapy — prior-antibiotic exposure → inappropriate empiric therapy (45.4% vs 21.2%) → higher hospital mortality (51.3% vs 34.0%) (PMID: 21499086). 3. Shock/vasopressor use, severe organ failure (SOFA) (PMID: 36773112, PMID: 36457059).

Complications: bacteremia, septic shock, ARDS, multi-organ failure; prolonged ventilation and hospitalization; in CF, progressive respiratory failure and death (median age at death in Italian CF registry 43–57 years) (PMID: 38742380, PMID: 42370441).

12. Treatment

First-line pharmacotherapy — anti-pseudomonal β-lactams. - Ceftolozane/tazobactam (3 g q8h) — non-inferior to meropenem in the phase 3 double-blind ASPECT-NP trial (NCT02070757) for ventilated HABP/VABP; for Gram-negative pathogens 28-day ACM 20.1% vs 25.8%, clinical cure 60.6% vs 57.1%, microbiologic eradication 73.0% vs 67.9%; P. aeruginosa comprised 25.0% of baseline LRT pathogens (PMID: 35022730). Efficacy held across renal-clearance and organ-failure subgroups (PMID: 34600585, PMID: 36773112). (NCIT: Ceftolozane-Tazobactam.) - Meropenem/carbapenems — comparator standard (PMID: 35022730). (NCIT: Meropenem.) - Other anti-pseudomonal agents: piperacillin-tazobactam, cefepime, ceftazidime, ceftazidime-avibactam, aztreonam, fluoroquinolones, aminoglycosides (guided by susceptibility, given high resistance rates).

For carbapenem-resistant P. aeruginosa (CRPA). Indian ICU guidelines (GRADE) favor non-polymyxin regimens for CRPA where efficacy is comparable but polymyxin toxicity is higher (42.1% vs 17.9%) (PMID: 42523687). Colistin remains active against many MDR isolates (80% colistin-S in an Egyptian VAP series) (PMID: 41877050).

Adjunctive / inhaled therapy. High-dose inhaled colistin followed by inhaled amikacin/tobramycin plus systemic therapy achieved clinical improvement and microbiologic eradication in MDR P. aeruginosa HAP/VAP despite in-vitro resistance, via high intrapulmonary concentrations (PMID: 42807670, PMID: 18060758).

Experimental / advanced therapeutics. - Anti-virulence monoclonal antibodies: fully human antibody cocktail targeting PcrV (T3SS tip), exotoxin A, and PA0833 gave broad-spectrum protection (PMID: 42662857); complement-activating CoMiX targeting Psl improved survival in murine pneumonia (PMID: 40961506). - Bacteriophage therapy: inhaled phage case series showed clinical/microbiological improvement without major adverse events (PMID: 41887374); murine efficacy depends on synergy with neutrophils, and alveolar macrophages can limit phage density (PMID: 40595615).

Supportive care: mechanical ventilation, oxygenation, hemodynamic support for sepsis, source control (device management), antimicrobial stewardship.

13. Prevention

Primary prevention (avoid acquisition). Ventilator-care bundles are central. The 2026 SIAARTI consensus endorsed subglottic secretion drainage and endotracheal cuff-pressure control; it did not recommend routine chlorhexidine oral care (outside cardiac surgery) and questioned selective digestive decontamination (SDD) (PMID: 42415225). Objectively beneficial measures include avoiding intubation, minimizing sedation, spontaneous awakening/breathing trials, early extubation and mobilization; oral chlorhexidine may increase mortality and stress-ulcer prophylaxis may facilitate pneumonia; SDD lowers VAP/mortality in low-resistance but not high-resistance ICUs (PMID: 31585480, PMID: 28759469, PMID: 32486132).

Secondary prevention. Early recognition/risk stratification (ISS, tracheostomy timing, CRP, ventilation duration) (PMID: 41978407); antimicrobial stewardship to preserve appropriate empiric therapy (PMID: 42393552).

Tertiary prevention. Infection control to prevent MDR spread (>90% of MDR-CRPA hospital-sourced; PMID: 41826861); CFTR-modulator therapy reduces chronic P. aeruginosa prevalence in CF (PMID: 42370441).

Immunization (experimental). No licensed vaccine. An OprF/PcrV bivalent DNA vaccine with hydrogel delivery reduced bacterial burden and improved survival in a murine pneumonia model (PMID: 38359491).

14. Other Species / Natural Disease

  • Taxonomy of pathogen: Pseudomonas aeruginosa (NCBI txid287); broad host range.
  • Cross-species susceptibility: P. aeruginosa pneumonia and infection occur across mammals; it is an opportunistic veterinary pathogen. Experimental infection is established in mice, rats, and zebrafish (PMID: 15972518, PMID: 40616692).
  • Comparative mechanisms: Innate sensing (TLR5, NLRC4 inflammasome) and T3SS-mediated cytotoxicity are conserved across mammalian hosts, enabling model-organism study.
  • Zoonotic potential: Environmental/opportunistic rather than classically zoonotic.

15. Model Organisms

Model Type Use / findings PMID
Rat acute lung injury Mammalian, in vivo T3SS-competent CHA vs exsA-null CHA-D1: T3SS drives ↑wet/dry ratio, ↑BALF protein, ↑mortality 15972518
Mouse acute pneumonia (intratracheal) Mammalian, in vivo Cmpk2-KO exacerbates ALI; NLRC4 inflammasome pathology; ASC/MSC, phage, mAb, vaccine efficacy 40616692, 33489931, 38359491, 40961506
Murine bone-marrow-derived macrophages In vitro/ex vivo ExoU induces mitochondrial damage 35130452
Zebrafish embryo Vertebrate Bacterial burden/survival; Cmpk2/STING-dependent phagocytosis 40616692
Human cell lines (A549, THP-1, MH-S, HEK293-TLR5) In vitro T3SS cytotoxicity (LDH), TLR5 signaling, alginate anti-phagocytosis 15972518, 37009499, 16239509

Recapitulation & limitations: Mouse/rat models faithfully reproduce acute T3SS-driven neutrophilic lung injury and inflammasome biology and are the workhorse for therapeutic testing; they less faithfully capture chronic human mucoid biofilm persistence, the full MDR resistance landscape, and human comorbidity context. Phage-therapy models further reveal immune–phage feedback (macrophages reduce phage density) that complicates translation (PMID: 40595615).

Key Findings (with statistical evidence)

F001 — T3SS is the principal acute virulence determinant. In a rat ALI model, the T3SS-expressing CHA strain caused significantly greater lung injury (higher wet/dry ratio and BALF protein at 12 h), increased A549 cytotoxicity, decreased clearance and increased mortality vs the isogenic exsA-null mutant CHA-D1. Four effectors — ExoS, ExoT, ExoU, ExoY — are canonical (PMID: 15972518, PMID: 25520826). The T3SS "is involved in lung injury, septic shock, and a poor patient outcome."

F002 — Leading MDR HAP/VAP pathogen. 3rd-ranked HAP pathogen in a 37-hospital Chinese cohort (13.73%); 39.2% of ICU VAP with 85.1% MDR in an Egyptian series; 2nd-ranked (34.0%) in a Saudi HA-GNB cohort (PMID: 41758741, PMID: 41877050, PMID: 42393552).

F003 — Ceftolozane/tazobactam non-inferior; mortality ~20–26%. ASPECT-NP: Gram-negative 28-day ACM 20.1% vs 25.8% (C/T vs meropenem); P. aeruginosa 25.0% of pathogens (PMID: 35022730).

F004 — Mucoid alginate/biofilm mediates immune evasion. In mucoid FRD1 vs algD mutant, alginate inhibited opsonic and non-opsonic phagocytosis by human and murine macrophages (PMID: 37009499).

F005 — Prevention rests on modifiable bundles; some components questioned. SIAARTI 2026 endorsed subglottic drainage and cuff-pressure control, not routine chlorhexidine; VAP incidence ~7–15% (PMID: 42415225, PMID: 30390751).

F006 — Host predisposition defines risk; CFTR/CF is the chronic paradigm. (PMID: 38702073, PMID: 9570172, PMID: 35927044).

F007 — Resistance and inappropriate initial therapy dominate prognosis. CR infections carry higher mortality across pathogens (PMID: 42707186); inappropriate initial therapy → 51.3% vs 34.0% mortality (PMID: 21499086); attributable VAP mortality ~30% (PMID: 18060758).

F008 — Emerging adjunctive/experimental therapies. Inhaled antibiotics, anti-virulence mAbs (PcrV/ETA/PA0833), DNA vaccine (OprF/PcrV), and bacteriophage therapy (PMID: 42807670, PMID: 42662857, PMID: 38359491, PMID: 41887374).

F009 — Innate sensing via TLR5 and NLRC4 drives IL-1β neutrophilic injury. TLR5 recognizes flagellin (PMID: 16239509); alveolar macrophages detect T3SS → NLRC4 → IL-1β (PMID: 42779855); ExoU damages mitochondria (PMID: 35130452); NLRC4 activation attenuates phagocytosis and drives pulmonary damage (PMID: 33489931).

Mechanistic Model / Interpretation

The nine findings cohere into a two-branch model in which the same pathogen produces two clinically distinct diseases depending on host context and bacterial phenotype. The acute branch is a cytotoxic + hyperinflammatory process: T3SS injection (F001, F009) both directly kills epithelial/immune cells (ExoU phospholipase, mitochondrial damage) and triggers NLRC4-inflammasome IL-1β release, while flagellin–TLR5 amplifies NF-κB signaling. The convergent output is neutrophil-driven destruction of the alveolar–capillary barrier → ARDS → death. This branch dominates the ICU/ventilated/neutropenic population (F002, F006).

The chronic branch is an immune-evasion + persistence process: mucoid conversion (mucA→alginate) shields the biofilm from phagocytosis (F004), producing lifelong infection in structurally abnormal airways (CF/bronchiectasis; F006). Here the host genome (CFTR) is the key permissive factor.

Superimposed on both branches is the resistance/therapy axis (F002, F003, F007): outcomes are governed less by intrinsic virulence than by whether the organism is MDR/CRPA and whether initial empiric therapy is appropriate. This reframes prognosis as substantially modifiable through stewardship, rapid diagnostics, and next-generation agents (F003, F008). Prevention (F005) closes the loop by reducing acquisition upstream of all mechanisms.

Evidence Base

Domain Key papers (PMID) Contribution
Virulence / T3SS 15972518, 25520826, 35130452 Establish T3SS effectors as drivers of acute lung injury and mitochondrial damage
Innate sensing 16239509, 42779855, 33489931, 22250084 TLR5/flagellin and NLRC4/IL-1β inflammatory axis; MUC1 counter-regulation
Chronic persistence 37009499, 38702073, 41010996, 42774065 Mucoid alginate/biofilm immune evasion; CF host context
Epidemiology / MDR 41758741, 41877050, 42393552, 41826861, 42523687 Rank, frequency and resistance burden
Treatment 35022730, 36773112, 36457059, 34600585, 42807670, 42523687 RCT efficacy (ASPECT-NP); inhaled/CRPA strategies
Prognosis 42707186, 21499086, 18060758 Resistance and inappropriate therapy raise mortality
Prevention 42415225, 31585480, 28759469, 30390751, 32486132 Bundle components, incidence
Emerging therapy 42662857, 40961506, 38359491, 41887374, 40595615, 40616692 mAbs, vaccine, phage, host-directed

Limitations and Knowledge Gaps

  • No dedicated dataset was analyzed; this is a literature-synthesis report, so all statistics derive from published cohorts/trials, each with their own design limitations (single-center retrospective series, subgroup analyses, non-inferiority framing).
  • Attribution vs association: P. aeruginosa-attributable mortality is hard to isolate from severe underlying illness; the ~30% VAP figure is not pathogen-specific.
  • Mechanistic data are largely model-organism/in-vitro (rat, mouse, zebrafish, cell lines). Human causal validation of the TLR5→NLRC4→IL-1β chain is inferential.
  • Host genetics beyond CFTR and inflammasome variants are poorly defined; no robust human GWAS for P. aeruginosa pneumonia susceptibility was identified.
  • Emerging therapies (mAbs, phage, DNA vaccine) rest on preclinical/case-series evidence without phase 3 RCT confirmation.
  • Ontology mappings (ICD, HPO, GO, CL, UBERON, NCIT) are expert-suggested here and should be curator-verified.

Proposed Follow-up Experiments / Actions

  1. Stratify prognosis by T3SS genotype (exoU vs exoS). Prospectively test whether exoU⁺ clinical isolates predict worse ARDS/mortality, linking F001 to human outcomes.
  2. Clinical validation of PcrV-targeted anti-virulence mAbs in ventilated HABP/VABP RCTs, building on preclinical protection (PMID: 42662857).
  3. Controlled trials of inhaled adjunctive antibiotics for MDR/CRPA VAP with pharmacokinetic/pharmacodynamic endpoints (PMID: 42807670).
  4. Phage–immune interaction studies to define dosing that overcomes macrophage-mediated phage clearance (PMID: 40595615).
  5. Biomarker-guided stewardship using CRP/IL-1β and rapid resistance genotyping to shorten time to appropriate therapy (addresses F007).
  6. Host-directed therapy targeting the NLRC4 inflammasome / Cmpk2–STING axis to rebalance protective vs damaging inflammation (PMID: 33489931, PMID: 40616692).
  7. Advance OprF/PcrV vaccine toward first-in-human trials in high-risk ICU/CF populations (PMID: 38359491).

Report compiled from 5 investigation iterations, 9 confirmed findings, and 61 reviewed papers. Evidence types span human clinical (surveillance cohorts, ASPECT-NP RCT), model organism (rat/mouse/zebrafish), in-vitro (A549/THP-1/MH-S/HEK293), and computational (multi-omics/GEO) sources.

Artifacts

Reference Validation

Checked with linkml-reference-validator 0.3.0rc3.

Outcome Count
References checked 49
Resolved 49
Unresolved (possible confabulation) 0
Unverifiable 0
References weighed for topical relevance 49
On topic 28
Off topic 0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome Count
Terms checked 29
Resolved 27
Unresolved (possible confabulation) 0
Obsolete 0
Unverifiable 2
Terms whose name was checked 11
Terms named correctly 2
Terms named as a different term 9

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

  • HP:0001945 (1 mention) - the report calls it "Common"; HP calls it Fever
  • HP:0012735 (1 mention) - the report calls it "Common"; HP calls it Cough
  • HP:0002094 (1 mention) - the report calls it "Common"; HP calls it Dyspnea
  • HP:0025440 (1 mention) - the report calls it "Common (VAP)"; HP calls it Warm reactive autoantibody positivity
  • HP:0001974 (1 mention) - the report calls it "Common"; HP calls it Increased total leukocyte count
  • HP:0011227 (1 mention) - the report calls it "Common (PMID: 42592972)"; HP calls it Elevated circulating C-reactive protein concentration
  • HP:0031977 (1 mention) - the report calls it "Diagnostic"; HP calls it Increased vertical cup-to-disc ratio - 0.9
  • HP:0033677 (1 mention) - the report calls it "T3SS-driven subset"; HP calls it Acute respiratory distress syndrome
  • UBERON:0002048 (1 mention) - the report calls it "Primary organ: Lung"; UBERON calls it lung**

Prefixes with no resolver

Terms carrying these prefixes were not checked either way, because no configured ontology covers them. An unrecognised prefix may name an ontology this run could not reach as easily as one that does not exist, so nothing here is evidence of fabrication: ORPHA.