Evaluation of Chromogenic VRE Medium versus Conventional Vancomycin E Test in Detection of Vancomycin Resistant Enterococci

Abstract

Background : Enterococci have become resistant to a wide range of antibiotics which include glycopeptides like vancomycin. The rapid increase of vancomycin resistance enterococci (VRE) compromises physicians to treat infections caused by these strains as the therapeutic options for VRE infections are very limited. Objectives : To evaluate the efficacy of chromogenic VRE medium in detection and identification of vancomycin resistant enterococci. Methodology :  the present study was conducted in Al Abbassia Fever Hospital, El Sayed Galal Hospital, Tanta University Hospital and Kafr El Sheikh General Hospital. Sixty enterococcal isolates were collected (thirty vancomycin susceptible, eight vancomycin intermediate resistant and twenty two vancomycin resistant isolates). Antibiotic susceptibility pattern for enterococcal isolates was done using disc diffusion method, chromogenic medium and MIC of vancomycin for vancomycin resistant and intermediate resistant isolates was determined by E test. Results : The most common isolated vancomycin resistant and intermediate resistant species was E. faecium (53.1%) followed by E. faecalis (40.6%). The highest rate of isolation of VRE was from urine (50.0%). VRE isolates were mostly recovered from ICUs (45.5), 41.7%, of the collected isolates were vancomycin resistant by disc diffusion method. Regarding E-test, out of fourty two vancomycin resistant and intermediate resistant by disc diffusion method 52.4% were resistant and 19% were intermediate resistant.  HiChrome VRE had 100.0% sensitivity and 83.3% specificity in identifying vancomycin resistant enterococcal isolates. Conclusion: We can depend on chromogenic media in both detection and identification of vancomycin resistant enterococci.