Identification of Enterococci faecalis&E. faeaciumpathogens viaTehran hospitals clinical samples by phenotypic and genotypic methods and Evaluation of Antimicrobial Susceptibility in 2016

Introduction: Epidemiology of Enterococcus infections has attracted much attention. Precise identification of pathogenic strains can be effective in the control process of microorganism antibiotic resistance. This study aimed to identify the Enterococcus species isolated from hospitals in Tehran and examine their antibiotic resistance pattern by phenotypic and genotypic methods. Methods & Materials: This study was performed on 400 clinical samples from different hospitals in Tehran during 20152016. Specific cultures and biochemical tests were used to identify Enterococcus, distinguish E. faecalis and E. faeacium species and PCR method was used to identify Enterococcus species. Antibiotic susceptibility was examined using Kirby-Bauer disc diffusion, and CLSI and vancomycin MIC were measured using broth dilution. Results: Of the 400 samples, 278 Enterococcus species were recognized. Phenotypic methods recognized 70.86% E. faecalis, 15.46% E. faeacium and 13.68% other species. PCR identified 72.3% E. faecalis, 10.43% E. faeacium and 17.27% other Enterococcus species. Results of the antibiograms showed the highest resistance (83.34%) to quinupristin/dalfopristin, and the lowest (1.41%) to linezolid. Also, resistance to vancomycin was observed in 5.95% with MIC ≥ 512 μg/ml in 9 cases. Conclusion: Rapid diagnosis can prevent massive outbreaks of Enterococcus. Given the prevalence of vancomycin resistance in Enterococcus, preventive measures are imperative. The right antibiotics should be prescribed according to the resistance patterns after susceptibility test is performed for each patient.