Determination of the biosafety of potential probiotic Enterococcus faecalis and Enterococcus faecium strains isolated from traditional white cheeses

The aims of this study were to characterize antibiotic resistance, determination of genotypic and phenotypic virulence characters; and to evaluate the safety of 12 Enterococcus faecalis and 8Enterococcus faecium strains isolated from Iranian and Turkish white cheeses. All strains were researched for production capability of cytolysin and gelatinase, biofilm formation and sensitivity against ten antibiotics. The presence of vancomycin resistance genes and virulence factors genes like cylA and cylB, esp, agg, asa1, EfaAfs, EfaAfm, cob, ccf, and hly were determined by polymerase chain reaction and sequence analysis. All the investigated strains were resistant to at least one class of antibiotic, and 40% of the strains were classified as multi drug resistant. E. faecalis RI 11, RI 17, RI 21 strains demonstrated both gelatinase and biofilm activities. Moreover, there was a significant correlation between gelatinase activity and the presence of gelE (P < 0.05). While ccf and asa1 genes were determined in all strains, efaAfm and clyB genes were not found in any strains. E. faecium RI 56, RI 58 and RI 59 strains were found to contain different molecular sizes of plasmid DNA. The phenotypic and genotypic characteristics of E. faecalis and E. faecium strains were determined in terms of functional and safety perspectives.