Occurrence of virulence factors and antibiotic resistances in Enterococcus faecalis and Enterococcus faecium collected from dairy and human samples in North Italy

The aim of this research was to study the incidence of potential virulence factors and antibiotic resistance in 38 Enterococcus faecalis and 43 Enterococcus faecium strains isolated from dairy products and human samples. The presence of the virulence factors agg, ace, esp, gelE, efaA and of the vanA and vanB genes was evaluated by PCR, while antibiotic resistance was tested by the disk diffusion method. Ent. faecalis displayed more virulence determinants than Ent. faecium, with the presence of multiple virulence traits. Virulence determinants were present in both human and dairy strains, while antibiotic resistance patterns of the two groups of strains were very different with a significant higher diffusion of resistances among human enterococci. Considering the results of our study, dairy enterococci cannot be considered the main potential source for dissemination of antibiotic resistances.