D-116. Molecular Characterization of Methicillin-Resistant Staphylococcus aureus Nasal Isolates from Turkey

A. Basustaoglu1, A. Kilic1, G. Mert1, Z. Senses1, H. Aydogan1, P. Appelbaum2;
1Gulhane Military Med. Academy, Ankara, TURKEY, 2Hershey Med. Ctr., Hershey, PA.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) colonize most frequently in the anterior nares of nose and cause serious infections all over the world. The aim of this study was to determine the nasal carriage rate of S. aureus and MRSA strains in Turkish elementary school children. Methods: We analyzed molecular characterizations of MRSA strains by using pulse field gel electrophoresis (PFGE), multi locus sequence typing (MLST), and staphylococcal chromosomal cassette mec (SCCmec) typing. The nasal swabs were obtained from 4050 children during the 4-months period in Ankara. In vitro antimicrobial susceptibility testing to 1 µg oxacillin and 30 µg cefoxitin was determined by a disc diffusion method in accordance with Clinical and Laboratory Standards Institute standards. The SCCmec types and the PVL genes were described by real-time TaqMan PCR method. PFGE typing of SmaI-digested DNA of MRSA was performed. MLST was performed using the standard primers as listed on the S. aureus MLST website (http://saureus.mlst.net/). Results: We found that the 1001 of 4050 (24.7%) children were colonized with S. aureus. Three S. aureus strains were resistant to oxacillin and cefoxitin. The rate of MRSA among all children was 0.07%. The MRSA strains revealed 3 different PFGE pattern. All MRSA isolates harbored SCCmec type IV element, but not PVL gene. The two MRSA isolate belonged to ST 30 whereas the other one was a unique type. Conclusion: The results of this study demonstrated that S. aureus nasal carriage rate was consistent with previous studies. However, MRSA carriage rate was low. This study also indicated that the ST30-type IV without PVL gene MRSA clone may be expected to spread in Turkish community.