Detection of VanA type vancomycin resistance among MRSA isolates from an emergency hospital in Egypt

AbstractResistance of methicillin-resistantStaphylococcus aureus (MRSA) strains to vancomycin is increasing and represents a major threat in the therapeutic fields. To assess susceptibility ofS. aureus to vancomycin and determine the occurrence ofVanA gene amongMRSA isolates. Agar diffusion method using cefoxitin disc (30  μg) was used to identifyMRSA among 100 isolates ofS. aureus. AmongMRSA, vancomycin resistance was determined by broth macrodilution andVanA gene was detected by PCR. Frequency ofMRSA was 92%. Phenotypically,MRSA isolates were vancomycin-susceptibleS. aureus (VSSA) (67.4%), vancomycin-intermediateS. aureus (VISA) (10.9%), and vancomycin-resistantS. aureus (VRSA) (21.7%). 17.4% ofMRSA wereVanA positive (75% wereVRSA and 25% wereVSSA). 82.6% ofMRSA wereVanA negative (76.3% wereVSSA, 13.2% wereVISA, and 10.3% wereVRSA). Sixty percent ofVRSA and 6.5% ofVSSA wereVanA gene positive but none of the detectedVISA isolates was carrier ofVanA gene. Percentage ofMRSA,VISA, andVRSA detected in this study is alarming and highlights the need for implementation of strict infection control measures to prevent further dissemination of such resistant strains in our region.
Source: Comparative Clinical Pathology - Category: Pathology Source Type: research