The survey of virulence factors of Enterococcus faecalis isolated from urine samples

Enterococcus faecalis is a normal commensal in the human intestinal flora but can leads to nosocomial infections. Several virulence factors have been described in E. faecalis, including aggregation substance(Agg), entrococcal surface protein(Esp), cytolysin (Cyl) having both hemolytic and bactericidal activity, and gelatinase(Gel). These factors act synergistically to enhance virulence, resulting tissue damage and tissue invasion. The aims of this study was phenotypic determination of virulence factors of E.faecalis isolates recovered from patients with urinary tract infections. This descriptive study were carried out in 95 clinical E. faecalis isolates recovered from patients with urinary tract infections in Shahid Beheshti hospital in Kashan, Iran, between 2007 and 2008. The production of biofilm, hemolysin and gelatinase by these isolates was also examined and the associated medical records of patients were retrospectively reviewed. Data were analyzed using Chi Square and Exact Fischer tests. Gelatinase activity was detected in 19 of the 95 (20%) E. faecalis isolates, hemolysin was detected in 42 of 95 (44.2%) E. faecalis isolates as beta hemolysis 35.8% and alpha hemolysis 7.4%, and 79 out of 95(83.2%) isolates showed weak, 6 out of 95(6.3%) moderate and 10 out of 95 (10.5%) strong biofilm formation. There was no significant correlation between biofilm formation and age, sex, previous history of antibiotic therapy, catheterization, production of haemolysin and gelatinase activity. No single factor was detected as virulence prediction. It seems that the factors act synergistically.