Community-acquired methicillin-resistant Staphylococcus aureus infections in France: emergence of a single clone that produces Panton-Valentine leukocidin.

To characterize the clinical and bacteriologic characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections, we reviewed 14 cases that were diagnosed in previously healthy patients during an 18-month period in France. Eleven patients had skin or soft-tissue infections. Two patients died of CA-MRSA necrotizing pneumonia. A case of pleurisy occurred in a child who acquired CA-MRSA from his mother, who had a breast abscess. The Panton-Valentine leukocidin genes and the lukE-lukD leukocidin genes were detected in all 14 isolates. The clonal origin of all of the isolates was demonstrated on the basis of their pulsotypes and antibiotic resistance profiles. All isolates had an agr3 allele. The combination of the Panton-Valentine leukocidin determinant (which encodes a virulence factor for primary skin infection and pneumonia) with the mecA gene (which confers antibiotic resistance and epidemicity) appears to have created a superadapted S. aureus strain that is spreading in the community.