Molecular Characterization Of Vancomycin-Resistant Enterococcus faecalis Among Inpatients At Iranian University Hospitals: Clonal Dissemination Of ST6 And ST422

Abstract

Purpose: Over the past two decades, enterococci have emerged as an important opportunistic pathogen causing life-threatening infections in hospitals. The purpose of the present study was to examine the prevalence of genes encoding virulence factor and molecular characterization of vancomycin-resistant E. faecalis strains isolated from hospitalized patients in Isfahan, the central city of Iran. Patients and methods: A total of 53 vancomycin-resistant E. faecalis isolates (VRE) obtained from clinical samples of hospitalized patients were characterized by phenotypic and genotypic methods, and 25 selected VRE isolates from internal and ICU wards were typed by multilocus sequence typing. Results: The efa was the most prevalent virulence gene (100) among isolates, followed by geld' (92.45), asa1 (90.56), ace (86.79), esp (75.47), cylA (39.62), and hyl (18.86). More than 80 of the isolates were HLGR. Multilocus sequence typing showed eight different sequence types including ST6, ST422, ST28, ST448, ST531, ST328, ST421, and ST495. STs were grouped into two clonal complex (CC) including CCA (ST6, ST422, ST448, ST531) and CCF (ST28, ST421) and two singletons (ST328, ST495). Conclusion: Our data indicated a high prevalence of virulence genes among STs described in this study. In addition, the molecular analysis demonstrated a relatively high genetic diversity among selected VRE strains from the ICU in comparison with the internal ward. Therefore, in order to prevent the colonization of virulent strains in the hospital environment, infection control procedures should be performed.