Background: The aim of this study was to determine the susceptibility of bacterial strains identified in community-acquired infections. Surveillance was made by a network of 32 medical analysis laboratories in the five departments of the French Region "Pays de la Loire".
Methods: All Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) strains isolated in these laboratories over a 4-year period, from January 2004 to December 2007, were included in the investigation.
Results: Eighty-four thousand and twenty-nine strains were collected: 90.6% of E. coli and 9.4% of S. aureus. E. coli isolates were mainly isolated from urine (97.2%). S. aureus isolates were more frequently isolated from pus (42.30%), from urinary samples (19.53%), or genital tract samples (14.36%). This study confirms the worrying E. coli evolution of resistance to quinolones. Indeed, during the study period, ofloxacin or norfloxacin susceptibility decreased gradually and the susceptibility rate to ciprofloxacin decreased slightly during and after 2006 (94.01% in 2005; 92.81% in 2006, and 91.62% in 2007). One thousand four hundred and thirty-five methicillin-resistant S. aureus (MRSA) strains were isolated. We observed a decrease of resistance to oxacillin: 20.73% in 2004 and 16.65% in 2006 (p<0.01). In 2007, this resistance to oxacillin seemed to increase (18.26%).
Conclusions: Our data confirms the serious need to monitor transmission of these strains between community and hospitals. A better knowledge of the epidemiological behavior of these BMR will contribute to better-adapted antibiotics strategies.