The study of probiotic characteristics of Enterococcus bacteria isolated from white cheese obtained from Turkey and Iran

In this study, from totally 12 white cheese samples obtained from different region of Turkey and Iran, after pre elimination tests, 62 bacteria probably being Enterococcus were isolated. After performing classic identification tests and with use of API 20 Strep kit, totally 42 Enterococcus bacteria with above 90% identification rate were identified as 28 Enterococcus faecium, 12 Enterococcus faecalis and 2 Enterococcus durans species. Probiotic characteristics such as antibiotic susceptibility, acid and hydrogen peroxide production, exopolysaccharide (EPS) production and antimicrobial activities of enterococci were investigated and due to mentioned tests 8 highly well characteristics Enterococcus species were selected and their identification were approved by 16S rRNA analysis method. Therefore, these identified Enterococcus species were tested for some other probiotic characteristics such as autoaggregation, coaggregation, acid and bile tolerance abilities.Antibiotic resistance among enterococci was examined with use of disc diffusion method. This test revealed that all of the tested Enterococcus bacteria were 100% resistant to gentamicin, streptomycin and polymixine B, but were 100% sensitive to vancomycin, teicoplanin, penicillin-G, ampicillin and chloramphenicol. The amount of acid produced by Enterococcus species was found between 0,46-1,26%, the amount of hydrogen peroxide production was found between 0,57-3,91µg/ml. The amount of EPS also produced by tested enterococci was determined between 34-362 mg/l. The antimicrobial activities of Enterococcus species on some of intestinal pathogenes and food contaminant bacteria (Escherichia coli ATCC 35218, Escherichia coli O157:H7, Bacillus subtilis ATCC 6633, Bacillus cereus RSKK 863, Salmonella enteritidis ATCC 13076, Salmonella typhimurium MU 80, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Listeria monocytogenes ATCC 7644) were observed by agar diffusion method. E. coli ATCC 35218, E. coli O157:H7, B. cereus RSKK 863, S. enteritidis ATCC 13076 and S. typhimurium MU80 bacteria were more affected by enterococcal antimicrobial activities than the others.The highest ratio of autoaggregation ability of tested Enterococcus species was found for E. faecium RI 53 (54,1%) and lowest ratio for E. faecalis RT 8 (22,1%). Due to coaggregation percent results, the highest one was between E. durans RI 43 and S. enteritidis ATCC MU:80 (52,4%) and the lowest one was between E. faecium RI 75 and E. coli O157:H7 (8,4%). In the study of acid tolerance ability of tested Enterococcus strains the most resistant to acid was found for E. faecalis RT 96 and the most sensitive one was for E. faecalis RT 8. In the case of bile tolerance ability, the most resistant to different bile salts concentrations was found for E. faecium RI 53 while E. faecalis RT 96 was mostly affected one from bile. E. faecium RI 42 was showed the higher viability in simulated gastric and intestinal juice.