Frequency of Vancomycin-Resistant Enterococci Isolated from Clinical Samples of Shahid Mohammadi Hospital through the E-Test Method

Introduction: Enterococci are gram-positive coccoid bacteria that are present in the normal flora of the gastrointestinal tract in human, and many mammals and birds, as well as the environment. Vancomycin-resistant Enterococci (VRE) are a major and rising problem in hospitals throughout the world. The present study aimed to investigate the frequency of strains of Enterococci and the pattern of drug sensitivity in clinical samples. Methods: This cross-sectional study was conducted on 54 samples of Enterococcus in 2012. The diagnostic kit of RapID STR System was used for identification of Enterococcus species. Antibiotic sensitivity was determined by Kirby-Bauer disk diffusion method according to CLSI instructions. E-Test was used to determine Vancomycin MIC. Results: Of the 54 isolates of Enterococci, the obtained strains included 38 E. faecalis (70.40%), 10 E. faecium (18.50%), 3 E. hirae (5.55%), one E. mudtii (1.85%), one E. durans (1.85%), and one E. avium (1.85%). Thirteen strains had vancomycin MIC>32 μg/mL. They had the highest resistance to gentamicin and cephalexin by 70.40% and the lowest resistance to linezolid by 3.70%. The highest resistant strain was obtained from urine (76.9%) and internal ward (46.1%). Conclusion: The substantial abundance of VRE isolated from the study area necessitates the performance of controlling measures.