Molecular epidemiology of community-onset methicillin-resistant Staphylococcus aureus infections in Israel.

Abstract

Data on community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) in Israel are scarce. The objective of this study was to characterize the major CA-MRSA clones in Israel. All clinical MRSA isolates detected in the community during a period of 2.5years (2011-2013) from individuals insured by a major health maintenance organization in Israel were collected, with additional data from medical records. Antibiotic susceptibility patterns and staphylococcal chromosomal cassette mec (SCCmec) typing were determined. SCCmec IV and V isolates were further typed by pulsed-field gel electrophoresis (PFGE), spa typing, and detection of a panel of toxin genes. MRSA were detected in 280 patients, mostly from skin infections. Patients with SCCmec IV (n = 120, 43%) were younger (p < 0.0001) and reported less contact with healthcare facilities. Almost all isolates were trimethoprim-sulfamethoxazole susceptible (98%). spa-CC032, a typical nosocomial MRSA clone, accounted for 28% of SCCmec IV. The two major CA-MRSA clones were t008 USA300 (13%) and t991 (10%); t991 was isolated mainly from children (75%), was Panton-Valentine leukocidin (PVL) negative but eta-positive, and was typically susceptible to most antibiotic groups. PVL-positive strains (n = 31) included mainly USA300 (52%) and t019 (13%). While multiple genetic lineages were evident among community-onset MRSA in Israel, approximately 20% are typical CA-MRSA clones, mainly USA300 and a local clone, t991.