Panton-valentine leukocidin-positive and toxic shock syndrome toxin 1-positive methicillin-resistant Staphylococcus aureus: a French multicenter prospective study in 2008.

The epidemiology of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) differs from country to country. We assess the features of the ST80 European clone, which is the most prevalent PVL-positive CA-MRSA clone in Europe, and the TSST-1 ST5 clone that was recently described in France. In 2008, all MRSA strains susceptible to fluoroquinolones and gentamicin and resistant to fusidic acid that were isolated in 104 French laboratories were characterized using agr alleles, spa typing, and the staphylococcal cassette chromosome mec element and PCR profiling of 21 toxin genes. Three phenotypes were defined: (i) kanamycin resistant, associated with the ST80 clone; (ii) kanamycin and tobramycin resistant, associated with the ST5 clone; and (iii) aminoglycoside susceptible, which was less frequently associated with the ST5 clone. Among the 7,253 MRSA strains isolated, 91 (1.3%) were ST80 CA-MRSA (89 phenotype 1) and 190 (2.6%) were ST5 CA-MRSA (146 phenotype 2, 42 phenotype 3). Compared to the latter, ST80 CA-MRSAs were more likely to be community acquired (80% versus 46%) and found in young patients (median age, 26.0 years versus 49.5 years) with deep cutaneous infections (48% versus 6%). They were less likely to be tetracycline susceptible (22% versus 85%) and to be isolated from respiratory infections (6% versus 27%). The TSST-1 ST5 clone has rapidly emerged in France and has become even more prevalent than the ST80 European clone, whose prevalence has remained stable. The epidemiological and clinical patterns of the two clones differ drastically. Given the low prevalence of both among all staphylococcal infections, no modification of antibiotic recommendations is required yet.