The investigation of prevalence of methicillin and vancomycin resistance in coagulase negative Staphylococci isolated from clinical samples of Shahrekord university hospitals, 2009

Vancomycin has been widely used in the treatment of infections caused by methicillin-resistant coagulase negative Staphylococci (MRCoNS). The emergence of vancomycin-intermediate and -resistant coagulase negative Staphylococci (VICoNS and VRCoNS, respectively) in various parts of the world, has caused great concern. In this study we investigated the prevalence of MRCoNS and Emergence of VICoNS and VRCoNS in Shahrekord Hospitals. Eighty eight coagulase negative Staphylococcus isolates were identified out of 284 Staphylococcus isolates collected from Shahrekod’s hospitals, Then, antimicrobial susceptibility pattern was determined for 12 antibiotics with Disk Diffusion method. Methicillin resistant strains were identified by several Disk diffusion, E-test and Real-time PCR. Vancomycin resistant strains were also identified by several Disk diffusion, Agar screening, E-test and Duplex PCR. Using the disk diffusion test, 100% of isolates were resistant to penicillin while the lowest resistance (33%) was found for ofloxacin. Fourty six CoNS strains were methicillin resistant and none of these isolates were vancomycin resistant and none had vanA/vanB genes demonstrated by PCR. This study showed a high prevalence of MRCoNS at Shahrekord hospitals, but, vancomycin resistance was not found.