الفهرس | Only 14 pages are availabe for public view |
Abstract Staphylococcus aureus (S. aureus) is an important cause of human disease, it can cause a wide range of infections from mild infections to life-threatening diseases. Over the last decade, methicillin resistant S. aureus (MRSA) starins have become endemic in hospital worldwide. Also it is now an endemic community pathogen in many geographical regions. MRSA is characterized by the presence of mecA gene, that encodes an alternative penicillin binding protein 2a (PBP2a) with low-affinity to -lactam antibiotics. All VRSA have been methicillin-resistant S. aureus (MRSA) that acquired vanA-mediated vancomycin resistance as a result of conjugation between vancomycin-resistant Enterococcus (VRE) and MRSA. The presence of an Inc18-like vanA plasmid in the donor VRE and pSK41-like plasmid in the recipient S. aureus appears to be important for the in vivo transfer of vanA from Enterococcus to S. aureus. The aim of this study is to determine the occurrance of vancomycin resistance among S. aureus isolated from Mansoura Emergency Hospital by both phenotypic and genotypic methods. Forty six (92%) MRSA isolates (detected by Cefoxitin disc diffusion) were tested for vancomycin resistance by using vancomycin disc (30μg). Twenty five (54.30%) isolates were identified as vancomycin sensitive Staph aureus (VSSA), whereas 21(45.7%) isolates were detected as vancomycin resistant Staph aureus (VRSA). PCR amplification of VanA gene among 46 methicillin resistant staph aureus isolates showed that 33 (71.7%) isolates were VanA negative, while 13 (28.3%) isolates were VanA positive. There was moderate agreement between results of phenotypic and genotypic method (K=0.54). Sensitivity, Specificity, PPV, and NPV of PCR for detection of vanA gene were 92.3%, 72.7%, 57.1%, and 96% respectively. Further studies are recommended to evaluate the presence of resistance genes other than VanA gene in phenotypically detected VRSA in our locality. |