Antimicrobial Resistance in Pseudomonas aeruginosa: A Genetic Perspective

A recent genomic analysis clarifies Pseudomonas aeruginosa’s resistance architecture and clinical consequences, positioning the organism as a pressing inpatient threat.

The investigators sequenced 124 clinical isolates—67 inpatient and 57 community—and performed short-read whole-genome sequencing with reference-based resistome profiling to map resistance and virulence determinants. The dataset identified co-occurring β-lactamase and virulence genes across clinical sources and is summarized in the study’s genetic landscape. Primary endpoints included β-lactamase gene prevalence and associations with clinical source.

Recurrent β-lactamase genes in the collection were blaOXA-4, blaOXA-1, and blaGES. These determinants reduce susceptibility to penicillins and many cephalosporins and can compromise some β-lactam/β-lactamase inhibitor combinations.

Virulence profiling identified aprA and lasA among strains linked to more severe clinical presentations. Isolates carrying these markers were associated with greater treatment challenges and, in aggregate, worse infection severity.

Resistance patterns were concentrated in nosocomial isolates, with a high prevalence of β-lactamase genes in hospital-derived strains. Notably, among nosocomial isolates the sample demonstrated 100% resistance to at least one β-lactam/β-lactamase inhibitor combination (amoxicillin/clavulanic acid), with similarly elevated rates for related agents—creating a significant stewardship and infection-control challenge for inpatient management.

Clinical implications include expanding rapid resistome-directed diagnostics or focused PCR panels to detect key β-lactamase genes and high-risk virulence markers.