Isolation and Antibiotic Susceptibility Pattern among Vancomycin Resistant Enterococci Isolated from Clinical Samples of Different Parts of Rasoul-E-Akram Hospital

Enterococci are among the normal microbial flora in human and animals digestive tract. The nosocomial pathogenicity of enterococci has emerged in recent years and has caused great concern due to developing resistance to many antimicrobial agents. The aim of this study was to investigate and identify the prevalence of VRE (vancomycin resistant enterococcus) within Enterococci isolates obtained from different parts of the hospital. Putative Enterococci (n=120) were isolated on Membrane Filter Enterococcus Selective Agar Medium and supplemented with 2, 4 and 8 µgr/ml vancomycin in medical samples. A total isolates passed the standard biochemistry tests for the genus and species as well as their specific primers. The antibiotic susceptibility was determined by the disc diffusion method for 8 antibiotics. Microbiologically-influenced corrosion (MIC) of vancomycin was also done using Agar-dilution assay by CLSI recommendations. Results showed that 38 and 84 of the isolates were E. faecium and E.faecalis, respectively. According to antimicrobial susceptibility tests 45, 88, 103, 42, 83, 73, 54 and 95 of the isolates were resistant to vancomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, penicillin, ampicillin and erythromycin, respectively. MIC test on 70% of the isolates was>256 µgr/ml. Despite the fact that the prevalence of VRE strains belongs to two species, E. faecium had high resistance to a broad range of antibiotics. The results of this study indicate the important role of medical samples as reservoirs of resistance elements. Early detection of VRE with their virulence trait will help in preventing the spread of vancomycin resistant enterococcus species and urgent infection control is required in hospital setting