Surveillance of methicillin-resistant Staphylococcus aureus (MRSA) and Enterobacteriaceae producing extended-spectrum β-lactamase (ESBLE) in Northern France: a five-year multicentre incidence study

Abstract

In order to measure the incidence of methicillin-resistant Staphylococcus aureus (MRSA) and of Enterobacteriaceae producing extended-spectrum β-lactamase (ESBLE), and to evaluate the impact of the national guidelines for multidrug-resistant bacteria (MDRB) prevention in hospitals of Northern France, a multicentre survey was conducted for three months every year starting in 1996, in volunteer hospital laboratories. All clinical specimens positive for MRSA and ESBLE were prospectively surveyed. During the five-year surveillance period, the overall proportion of MRSA was 38.4% in the 28 534 strains of S. aureus, and that of ESBLE was 11.4% in the 6121 strains of Klebsiella pneumoniae and 47.7% in the 2353 strains of Enterobacter aerogenes. The overall incidence rates of clinical specimens positive for MRSA, ESBL- K. pneumoniae and E. aerogenes were 0.84, 0.05 and 0.12/1000 hospital-days (HD), respectively. In the 23 hospitals that participated in the survey every year, the proportion and incidence of MRSA increased from 35.6 to 41.0% and from 0.71 to 0.96/1000 HD ( P<0.001). Conversely, the incidence of ESBLE decreased. Hence, despite recommendations as for isolation precautions, MRSA remains poorly controlled and requires more effective measures.