NOSOCOMICAL Pseudomonas aeruginosa frequently translocates between lung and gut in hospital patients, reshaping sepsis risk.
Mapping Within-Host Spread Across Body Sites
In this metagenomic cohort study, investigators analyzed paired respiratory and gut samples from 256 hospital patients to characterize within host diversity of nosocomial Pseudomonas aeruginosa. Genomes were successfully recovered from 84 patients, revealing 27 individuals in whom the same clone appeared in multiple body sites. Simulation modelling suggested that most shared clones reflected within patient translocation rather than repeated acquisition from the wider hospital environment.
Ancestral reconstruction methods indicated that Pseudomonas aeruginosa usually established first in a respiratory niche. From there, the most probable direction of spread was lung to gut, rather than gut to lung. This pattern points to lower respiratory tract infections as an important source of subsequent gastrointestinal colonization in vulnerable inpatients.
Nosocomial Pseudomonas Aeruginosa Translocation Patterns
Analysis of within patient variation showed strong enrichment of mutations in genes linked to antimicrobial resistance, regardless of whether isolates originated from respiratory or gut specimens. These findings suggest that selective pressures within the hospital setting can favor resistant Pseudomonas aeruginosa clones that retain the ability to occupy multiple anatomic niches.
The authors report substantially higher rates of body site translocation than previously appreciated. Persistent gut colonization with Pseudomonas aeruginosa following lower respiratory tract infection may therefore represent a sustained reservoir of infection and a major risk factor for sepsis, particularly in critically ill or immunocompromised patients. For frontline clinicians, these data highlight the importance of viewing nosocomial Pseudomonas aeruginosa as a dynamic within host pathogen that can relocate between body sites over time. Future work that clarifies how best to detect and disrupt this lung to gut translocation could help refine infection prevention strategies and mitigate downstream sepsis risk in vulnerable hospital populations.
Reference: Fisher LWS et al. High frequency body site translocation of nosocomial Pseudomonas aeruginosa. Nature Communications. 2025;16:9862.
