1. Emergence of extensive-drug-resistant Pseudomonas aeruginosa in a French university hospital.
- Author
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Vettoretti, L., Floret, N., Hocquet, D., Dehecq, B., Plésiat, P., Talon, D., and Bertrand, X.
- Subjects
MOLECULAR epidemiology ,PSEUDOMONAS aeruginosa ,PULSED-field gel electrophoresis ,INFECTIOUS disease transmission ,LACTAMS ,UNIVERSITY hospitals ,DRUG resistance - Abstract
The aim of this study was to describe the molecular epidemiology and the mechanisms of resistance to β-lactams of emerging extensive-drug-resistant Pseudomonas aeruginosa (XDRPA) in a tertiary-care university hospital over a three-year period. Analysis included antimicrobial susceptibility profiling and pulsed-field gel electrophoresis (PFGE). Resistance mechanisms to β-lactams were identified: production of naturally occurring and acquired β-lactamases, overproduction of MexAB-OprM and MexXY efflux systems and loss of porin OprD were assessed. Eighteen patients were colonised or infected with XDRPA which remained susceptible to colistin and, to a lesser extent, to rifampicin. β-lactam resistance was, in most cases, due to the overproduction of AmpC, overproduction of the MexXY efflux system and loss of porin OprD. One isolate produced the class D extended-spectrum oxacillinase (OXA-ESBL) Oxa-28, but none produced metallo-β-lactamase (MBL) or class A extended-spectrum β-lactamase (ESBL). The XDRPA clustered in eight PFGE patterns and both the acquisition and loss of resistance determinants was observed within a single clone during its spread. The emergence of XDRPA isolates in our university hospital has been characterised by genotypic heterogeneity, variation of mechanisms of resistance to β-lactams in a single clone and the predominance of chromosomally encoded resistance mechanisms [ABSTRACT FROM AUTHOR]
- Published
- 2009
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