Comparison of genotypic diversity, vancomycin resistance and virulence factors of enterococci from food and clinical sources

In this research, genetic diversity and incidence of potential virulence factors, vancomycin resistance were studied and also evaluated a possible correlation that can exist between vancomycin resistance and virulence factors between 51 Enterococcus spp. food and 50 human clinical originated Enterococcus faecium strains in Adana Region. Identification and antimicrobial susceptibility tests were performed by Vitek-II and disc diffusion method. Minimum inhibitory concentrations of clinical isolates were confirmed by E-test, and the presence of vanA and vanB as well as virulence genes cylA, asa1, esp, gelE, hyl were investigated by PCR method. Genetic diversity within the each groups; 6 clusters of colonization and 5 clusters of food isolates were found to be closely related. Although, no genetic relation was found among foods and human clinical infection isolates; 2 clusters of foods and human intestinal isolates were found to be closely related by Pulsed Field Gel Electrophoresis method. Except for the cylA gene, all other virulence genes and vancomycin resistance were higher in human strains, and a correlation was observed between multivirulence genes and hemolytic activity. For all strains, a correlation existed between the esp gene positivity and vancomycin resistance, while for only E. faecium, esp, hyl gene positivity and vancomycin resistance correlation could be seen. Finally, vancomycin sensitive E. faecium strains from food colonize in human, acquire vanA and vanB resistance genes and might be a reservoir for vancomycin resistance and food originated enterococci may be a potential source for dissemination of gelE, asa1 and hyl virulence genes.