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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]

The objective of this study was to describe trends for the years 2004 to 2006 in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and Enterobacteriaceae-producing extended-spectrum β-lactamase (ESBLE) in a large hospital network (70 hospitals in eastern France). The incidence of MRSA per 1,000 patient-days decreased significantly from 0.55 in 2004 to 0.45 in 2006. This trend was observed in medicine and surgery units, whereas MRSA incidence was stable in intensive care, paediatric and obstetric units. The incidence of blood cultures positive for MRSA remained stable at 0.04 per 1,000 patient-days. Conversely, the incidence of ESBLE increased significantly from 0.04 in 2004 to 0.08 in 2006. This increase was caused by the spread of ESBLE-producing Escherichia coli. The mean consumption of alcohol-based gel and solution (ABS), expressed in litres per 1,000 patient-days, was 3.3 in 2002, 4.5 in 2003, 5.4 in 2004 and 6.4 in 2005. There was no association between the consumption of ABS and MRSA incidence. These findings suggest that the French recommendations for the control of multi-drug-resistant bacteria (MDRB) have been effective in reducing, or at least stabilising, the incidence of MRSA in an international context of general increase. However, the diffusion of ESBLE-producing E. coli is a matter of concern and should be carefully monitored. [ABSTRACT FROM AUTHOR]

Objective: In 1999, we conducted a retrospective drug utilization review to determine the volume and pattern of vancomycin use in a university affiliated hospital in eastern France. Methods: Total vancomycin use was determined and expressed as vancomycin courses per 100 admitted patients and defined daily doses (DDD) of vancomycin per 100 patient days. The indication for vancomycin use was classified as appropriate or inappropriate according to the guidelines issues by the HICPAC. Results: A total of 311 vancomycin courses were given, as 2098 DDD, giving crude incidences of 1.17 courses per 100 admitted patients and of 1.19 defined daily doses per 100 patient days. The frequency of appropriate courses was 66.7%. Of the 63 inappropriate courses of vancomycin, 39.7% and 28.6% were empiric therapy for nosocomial and community acquired infections, respectively, 20.6% and 6.3% were specific therapy for nosocomial and community acquired infections, respectively, and 4.7% were prophylactic. Conclusions: This study shows that vancomycin use in our hospital resulted in a lower selection pressure than has been reported for US university affiliated hospitals and that comprehensive programs to improve use of vancomycin are needed in our institution. [ABSTRACT FROM AUTHOR]