What this entity is
Pseudomonas aeruginosa is the canonical organism name for the cystic-fibrosis airway pathogen targeted by protective commensal formulations designed to achieve competitive exclusion. 1
Known aliases include PA and P. aeruginosa. 1
A stable external identifier was not provided in the source report. 1
Key facts from the formulation-design study
- The study targeted P. aeruginosa using planktonic inhibition assays, carbon-utilization profiling, growth kinetics, patient metagenomics and metatranscriptomics, pairwise interaction data, and pangenome analysis. 1
- The experiments primarily used the PA14 strain under synthetic cystic-fibrosis sputum conditions. 1
- PA14 preferentially used amino acids, with endpoint optical-density values of 0.60 for proline, 0.56 for histidine, 0.46 for ornithine, 0.40 for glutamate, 0.36 for aspartate, 0.36 for isoleucine, and 0.35 for arginine. 1
- Glucose supported an endpoint optical density of 0.22, while threonine, methionine, cysteine, serine, and glycine each supported essentially no growth at less than 0.07. 1
- Across 1,796 lung or respiratory P. aeruginosa genomes, amino-acid catabolic pathways were 97.4% conserved, and proline utilization was complete in 97% of lung isolates. 1
- Lung P. aeruginosa showed pathway losses for sorbitol (-0.165), mannitol (-0.204), and gluconate (-0.185), consistent with metabolic streamlining toward amino-acid dependence. 1
- The amino-acid target set was invariant across virulence backgrounds: GapMind score differences between ExoU+ and ExoS+ isolates were less than 0.03, with zero FDR-significant pathways. 1
- Among 291 cystic-fibrosis genomes, 94% were ExoS+ and 5% were ExoU+. 1
- Among 643 annotated PROTECT genomes, 304 (47%) were PAO1-like, 48 (7%) were PA14-like, and 291 (45%) were intermediate; among classifiable isolates, 86% were PAO1-like. 1
- The PROTECT isolates were distributed across broader lung-P. aeruginosa diversity in a Pfam-based tree of 165 genomes rather than clustering in one lineage. 1
- The study identified metabolic competition as a real but incomplete mechanism for inhibiting PA14: metabolic overlap with PA14 predicted planktonic inhibition across 142 isolates with correlation r = 0.384 and p = 2.3×10⁻⁶, while approximately 73% of inhibition variance remained unexplained by metabolism alone. 1
- Adding genus-level taxonomy increased the metabolic model from R² = 0.274 to R² = 0.360, while five-fold cross-validation yielded CV R² = 0.145 ± 0.142. 1
- PA14 outgrew the average commensal on every one of the 22 tested substrates, and no tested amino acid or simple sugar provided a clear commensal growth advantage; the most selective substrates had commensal-to-PA14 ratios of only 0.77–0.96. 1
- Genomic comparisons identified myoinositol, xylitol, xylose, arabinose, fucose, and rhamnose as pathways complete in at least one core commensal species but absent or nearly absent in PA14; PA pathway completeness was 0% for myoinositol, xylitol, xylose, and arabinose, and 1% for fucose and rhamnose. 1
- The source report proposed testing PAO1 and 3–5 mucoid clinical P. aeruginosa isolates because PA14-based inhibition measurements had not been validated against PAO1 or ExoS+ clinical strains. 1
- The report notes that the inhibition assays were planktonic, whereas P. aeruginosa in cystic-fibrosis lungs primarily occupies structured biofilms. 1
Cross-study metabolic, ecological, and literature evidence
A separate seven-organism GapMind pilot found that P. aeruginosa strain PS had 18/18 amino-acid biosynthesis pathways complete (100%), with 745 GapMind predictions. This supports the broader evidence for substantial amino-acid metabolic capacity, while refining it by distinguishing biosynthetic completeness from the lung-isolate study’s amino-acid catabolic conservation. 2
The result is computational and limited to a seven-organism pilot, so it does not establish that these pathways are essential for viability or that all P. aeruginosa strains share the result. 2
A larger GapMind analysis of 12,732 genomes across 433 Pseudomonas species clades supports the formulation study’s evidence for carbon-use streamlining: the P. aeruginosa group had substantially less complete xylose, arabinose, myo-inositol, mannitol, and sorbitol pathways than the P. fluorescens/putida group, while amino-acid and core organic-acid pathways remained near-universal. 3 The same analysis refines the host-associated interpretation by showing that the dominant carbon-profile separation is between Pseudomonas s.s. and Pseudomonas_E, rather than a clean lifestyle separation within Pseudomonas_E. 3 Carbon profiles nevertheless retained a modest ecological signal among free-living and plant-associated species: a 999-permutation test gave p = 0.006, but a four-class Random Forest reached balanced accuracy of 0.408 +/- 0.169 versus a 0.250 chance baseline. 3
The lignin-enrichment experiment supports the condition-specific-fitness evidence: Pseudomonas increased from less than 0.1% in the base community to 39.3% after one lignin-enrichment round and reached 23–53% across enriched conditions, but fell from 39.3% to 23.0% when labile carbon was added. 4 This community-level response refines the metabolic-competition claims by showing that Pseudomonas enrichment depends on the carbon regime; the study inferred lignin association from taxonomy rather than directly measuring pathway genes. 4
PaperBLAST lists P. aeruginosa PAO1 as the third-leading bacterium by literature coverage, with 5,928 papers. This supports its status as a model organism and refines the formulation study’s recommendation to test PAO1 by showing that PAO1 is prominent in the literature, while not establishing that it represents cystic-fibrosis clinical diversity. 5
Related pages
This organism is the target of the protective-community strategy described in Rational Design of Protective Microbiome Formulations for Competitive Exclusion of *Pseudomonas aeruginosa* in Cystic Fibrosis Airways. 1
The seven-organism pathway analysis is summarized in Essential Metabolome: GapMind Pathway Analysis Across Essential-Gene Organisms. 2
The comparative Pseudomonas carbon-ecology analysis is summarized in Carbon Source Utilization Predicts Ecology and Lifestyle in Pseudomonas. 3
The lignin-community experiment is summarized in Lignin Enrichment and Ecological Memory in Microbial Communities. 4
The PaperBLAST literature-coverage analysis is summarized in PaperBLAST Data Explorer — Literature Coverage Bias in Protein Sequence Space. 5
The findings relate to condition-specific-fitness through substrate-specific growth, inhibition, lung adaptation, and carbon-regime-dependent community enrichment. 1,4
They relate to ecotype-environment-gene-content through subgenus-associated carbon pathway profiles and the limited environment signal among free-living species. 3
They relate to environment-embedding-geography through PCA, permutation testing, and classification of isolation environments from carbon-pathway profiles. 3
They relate to multi-omics-integration through combined inhibition, utilization, kinetics, metagenomics, metatranscriptomics, pangenome evidence, and paired bacterial 16S and fungal ITS community profiling. 1,4
They relate to pangenome-integration through comparisons of 1,796 lung or respiratory genomes and commensal pangenomes, and the 12,732-genome Pseudomonas carbon-pathway matrix; the lignin study proposes mapping enriched Pseudomonas and other genera to gene annotations in kbase_ke_pangenome. 1,3,4
They relate to metabolic-model-gapfilling through GapMind comparisons of pathway completeness between PA14 and candidate commensals, the PS pilot result, and standardized carbon-pathway predictions. 1,2,3
They relate to gene-function-acquisition-depth because PaperBLAST quantifies the concentration of functional literature on organisms and protein families, including the prominent but potentially nonrepresentative coverage of PAO1. 5