Molcular typing of methicillin-resistant staphylococcus aureus strains

Methicillin resistant S. aureus (MRSA) is a major pathogen causing both nosocomial and community-acquired infections. MRSA strains have emerged worldwide and became resistant to a variety of antibiotics. The most important features of this bacterium are becoming colonization and able to expend clonally.The aim of this study was to determine the molecular characteristics of 12 MRSA strains isolated from milk samples (n=90) and nasal samples of cows (n=56) with subclinical mastitis obtained from Adnan Menderes University, Faculty of Veterinary Medicine, Department of Microbiology between January-May 2010, and from nasal samples (n=35) of veterinarians and farm workers using pulsed field gel electrophoresis (PFGE), staphylococcal protein A (spa), multi locus sequence typing (MLST) and staphylococcal chromosome cassette mec (SCCmec) typing. SCCmec types of these strains were investigated by multiplex polymerase chain reaction (PCR). The spa genes encoding for protein A and 7 housekeeping genes (arcC, aroE, glp, gmk, pta, tpi ve yqiL) for MLST were amplified by PCR and sequenced. PFGE analysis of all 12 MRSA isolates produced four distinct pulsotypes designated as pulsotypes A-D. The pulsotype A (n=7) strains detected the most prevalent sequence type (ST) were ST 239, spa type t030 and SCCmec III except one. The pulsotype B strains (n=3) were ST1294, t459 and SCCmec III, the pulsotype C (n=1) strains were ST1940, t660, SCCmec III detected. The remaining pulsotype D (n=1) strains were ST737, t542, SCCmec II. spa type t030 which were the most common spa type in Turkish hospitals and east country. This clone, which is rare in USA and Europe, called as ?Turkish Clone?. It was thought that the high amount of MRSA strains originated from hospitals would be humanosis. Two bovine milk and nasal swabs obtained from veterinarians who looked after the animal, infected with the same clone, a total of 7 strains of MRSA clonal propagation has shown that property. Consequently, it can be said that t030 and ST239 was the most common spa and MLST types which isolated from cow milk and nasal swabs and nasal swabs from workers of these farms in Aydın.