prevalence of virulence factors and vancomycin-resistant genes among enterococcus faecalis and e. faecium isolated from clinical specimens

background: the aim of this study was to determine the occurrence of virulence determinants and vancomycin- resistant genes among enterococcus faecalis and e. faecium obtained from various clinical sources. methods: the study was performed on the 280 enterococcal isolated from clinical specimens in hamadan hospitals, western iran in 2012-14. antibiotic susceptibility testing was performed using disk diffusion and minimal inhibitory concentration (mic) methods. the presence of vancomycin-resistant genes and virulence genes was investigated using pcr. results: totally 280 enterococcal isolates were identified as follows: e. faecalis (62.5%) , e. faecium (24%) and enterococcus spp (13.5%). the results of antibiotic susceptibility testing showed that resistance rates to vancomycin and teicoplanin in e. faecalis and e. faecium isolates were 5% and 73%, respectively. of sixty vancomycin-resistant enterococci strains, fifty-one isolates were identified as e. faecium ( vrefm ) and nine as e. faecalis ( vrefs ). prevalence of esp, hyl, and asa 1 genes were determined as 82%, 71.6%, and 100%, respectively in e. faecium strains; and 78%, 56/6%, and 97%, respectively in e. faecalis strains. conclusion: the increased frequency of vref, as seen with rapid rise in the number of vana isolates should be considered in infection control practices.