Multicenter Genomic Analysis of Carbapenem-Resistant Pseudomonas aeruginosa in Austrian Community Hospitals Reveals Limited Carbapenemase Prevalence and Absence of Interhospital Clonal Spread

Antibiotics (basel, Switzerland): Volume 15, Issue 5, Page 516

Background/Objectives: In Europe, Pseudomonas aeruginosa is the second most common cause of ventilator-associated pneumonia in intensive care units. Intrinsic antibiotic resistance and acquired carbapenemases can lead to high mortality. To guide more targeted antimicrobial therapy and adequate infection control measures, we performed a multicenter study on the prevalence and genetic basis of carbapenem resistance among P. aeruginosa (CR-PA) across 17 community hospitals in Austria. Methods: During a 3-month period, we collected 621 P. aeruginosa isolates from 560 patients. Antibiotic susceptibility testing was performed according to EUCAST guidelines, and all CR-PA isolates were subjected to whole genome sequencing. Results: Antibiotic susceptibility testing revealed carbapenem resistance in 5.41% (36/621) of the investigated P. aeruginosa isolates. Only 3 produced a carbapenemase (2 Verona Integron-encoded Metallo- ß-lactamases and 1 Imipenemase Metallo-ß-lactamase) and carried a carbapenemase-encoding gene. Among the studied P. aeruginosa isolates there was a high genetic diversity, excluding a single driving epidemic lineage in the included Austrian hospitals. Conclusions: The absence of interhospital clonal dominance suggests that carbapenem resistance emerged independently in different centers, likely driven by local antibiotic selection pressures rather than regional clonal spread.

DOI: 10.3390/antibiotics15050516