Molecular analysis of methicillin resistant s.aureus (mrsa) and coagulase negative staphylococci isolated from intensive care unit

In recent years, it was reported that methicillin resistant S. aureus (MRSA) strains develop resistance seriously to aminoglycosides and quinolones. In this situation, detection of strains epidemiologically related with MRSA and CoNS in vitro and distinguishing of these strains from unrelated strains has a big importance. Performance of similar studies in all center, benefit to control nosocomial infections. A total of 57 MRSA and CoNS strains isolated from blood samples of patients in intensive care units of our hospital between October-December 2004 were included in this study. In all isolates oxacillin and cefoxitin by disc diffusion test, detection of mec A gene by PCR and epidemiologically relationship of strains by PFGE were studied. Two basic clones were determined by PFGE in intensive care units, our hospital. Clone A was 68% and Clone B was 32% of all strains. For MRSA mec gene positivity was 76%, for CoNS was 59.3% was determined. By detecting methicillin resistance, disc diffusion test may give incorrect result, so it is necessary to investigate detection of the mec A gene by PCR. Determination of MRSA and CoNS in internal intensive care unit and being determined same clones showed that MRSA and KNS may be colonized in decayed materials in this unit and at the same time health care may be carriers of them.