Who are the carriers of MRSA in the community? A prospective study in the Pays de la Loire region of France

The aim of this study was to determine the demographic characteristics of methicillin-resistant Staphylococcus aureus (MRSA) carriers in the community, to assess their risk factors and possible past hospitalization history and to describe the different resistance phenotypes of community isolates of S. aureus. Data were collected over the course of 16 months (from June 2005 to September 2006) in the Pays de la Loire region of France by Med-Qual, a network of private biological analysis laboratories. This work was based solely on the analysis of strains isolated in the community as opposed to isolates from private facilities such as nursing homes or hospitals. The antimicrobial susceptibility results for a total of 313 MRSA isolates were included in this study. The isolates were most frequently recovered from skin and soft tissue infections (41.2%), urine (38.3%) and genital samples (8.3%). We distinguished 36 patients without classical risk factors (WRF), such as demographic individual medical, healthcare exposure, carried MRSA, from the other 277 patients with at least one risk factor (RF). WRF MRSA patients were younger than RF patients and an infection was more often found among WRF patients. MRSA strains isolated from RF patients were resistant to ofloxacin in 81.1% of cases, whereas only 50% of the MRSA strains isolated from WRF patients were resistant (p <0.001). Nine resistance phenotypes were observed among the 313 MRSA strains. MRSA resistance profiles in the community have evolved in recent years. Therefore, it is necessary to study the resistance phenotypes of the circulating strains in order to adapt therapeutic care in the community.