Incidence of virulence in bacteriocin-producing enterococcal isolates

Enterococci isolated from a total number of 68 dairy products and 28 human fecal samples were screened for bacteriocin production. The incidence of the bacteriocin-production trait was highest among the cream samples (33.51%), followed by dahi samples (15.55%), raw milk samples (9.51%), Cheddar cheese (9.2%) samples and human feces (4.72%). The isolates showed antilisterial effect besides activity against other lactic acid bacteria. Sixty potent bacteriocin-producing isolates of enterococci were evaluated for the incidence of virulence characters for their safe exploitation. None of the isolates was found to exhibit gelatinase, DNAse or beta-hemolysis activity. Furthermore, only 4 bacteriocin-producing isolates among 60 were observed to be vancomycin-resistant. It was concluded that bacteriocin-producing Enterococcus strains lacking hemolytic activity and not carrying vancomycin resistance genes may be safely exploited as starter cultures, co-cultures or probiotics.