Isolation and characterization of potential probiotic enterococci strains from soft cheese flora

This study was conducted to determine the in-vitro probiotic properties of Enterococcus faecium strains isolated from soft cheese. To evaluate the safety of Enterococcus strains, we compared the pathogenic genes, antimicrobial susceptibility of the probiotic strains to those of clinical isolates, and their antimicrobial activity against food-borne pathogenic and spoilage bacteria. Enterococcus strains were identified and evaluated in vitro for biochemistry methods acid, bile salts, lysozyme and pancreatin tolerance. One hundred and three strains were identified as E. faecium, and none of them were no vancomycin-resistant, and no pathogenic genes – such as cylA, asa1, gelE, ace and cpd – were found. The isolates showed good viability at 120 and 240 min of incubation with pH 3.0, and were able to resist 0.3% and 0.1 g/ml of bile salts and pancreatic enzyme, respectively. One observed strong autoaggregation phenotype, and the isolates demonstrated high activity against L. innocua, L. monocytogenes, E. faecalis S. aureus, Salmonella Enteritidis and Salmonella Typhimurium. The results instigate the continuity of studies of E. faecium isolates in order to obtain a known probiotic strain.   Key words: Enterococcus, good bacteria, pathogenic genes, foods, antimicrobial activity.