Molecular epidemiology of Pseudomonas aeruginosa isolated from infected ICU patients: a French multicenter 2012 –2013 study

AbstractAlthoughPseudomonas aeruginosa has a non-clonal epidemic population structure, recent studies have provided evidence of the existence of epidemic high-risk clones. The aim of this study was to assess the molecular epidemiology ofP. aeruginosa isolates responsible for infections in French ICUs, regardless of resistance patterns. For a 1-year period, all non-duplicateP. aeruginosa isolated from bacteremia and pulmonary infections in ten adult ICUs of six French university hospitals were characterized by antimicrobial susceptibility testing and genotyping (MLST and PFGE). We identified β-lactamases with an extended spectrum phenotypically and by sequencing. The 104 isolates tested were distributed in 46 STs, of which 7 epidemic high-risk (EHR) clones over-represented: ST111, ST175, ST235, ST244, ST253, ST308, and ST395. Multidrug-resistant (MDR) isolates mostly clustered in these EHR clones, which frequently spread within hospitals. Only one ST233 isolate produced the carbapenemase VIM-2. PFGE analysis suggests frequent intra-hospital cross-transmission involving EHR clones. For ST395 and ST308, we also observed the progression from wild-type to MDR resistance pattern withi n the same PFGE pattern. Molecular epidemiology ofP. aeruginosa in French ICUs is characterized by high clonal diversity notably among antimicrobial susceptible isolates and the over-representation of EHR clones, particularly within MDR isolates, even though multidrug resistance is not a constant inh...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research