Molecular characterization of the virulence genes gelE and cylA in the Enterococcus species isolated from clinical samples

Background: In recent years, Enterococcus spp. are considered as the most important nosocomial pathogens. Different factors are involved in the pathogenesis of these bacteria among which hemolysin (hyl) or cytolysin (cylA) and gelatinase (gelE) are the most important ones. The current study aimed to evaluating the prevalence of virulence genes cylA and gelE in the Enterococcus species isolated from patients by the polymerase chain reaction (PCR) technique. Methods: The study evaluated a total of 300 clinical samples isolated from patients hospitalized in Milad and Baqiatallah hospitals, Tehran, Iran. The isolated species were identified by culturing and routine biochemical methods. The antibiotic susceptibility testing was performed using the standard disk diffusion method, according to the guidelines of Clinical and Laboratory Standards Institute. The prevalence of cylA and gelE genes was assessed by PCR using specific primers. Results: Out of 300 clinical samples, 143 were identified as enterococci in which 128 (89.51%) species were E. faecalis and 15 (10.48%) E. faecium. Results of the antibiotic susceptibility testing showed the highest resistance against tetracycline and quinupristin, and the lowest resistance to linezolid, teicoplanin, and nitrofurantoin in the isolated enterococci. Of 143 isolated species, 114 (79.72%) harbored gelE and 80 (55.94%) carried cylA. Conclusion: Results of the current study showed that most species isolated from patients carried the important virulence factors of gelE and cylA, although other virulence factors can affect the incidence of infection.