Antibacterial Activity of Strains Isolated from Mongolian Yogurt against .

Worldwide interest in the use of functional foods containing probiotic bacteria such as and for health promotion and disease prevention has increased significantly. Probiotics have demonstrated beneficial properties including strengthening the body's natural defense system, inhibiting the growth of pathogenic bacteria, and regulating mental activity, but their effects on the human vagina have not been fully elucidated. The primary purpose of our study was to isolate strains from old yogurt, a traditional dairy product, and investigate their probiotic potential with respect to the human vaginal system. Four () strains, named ZX1, ZX2, ZX27, and ZX69, were isolated from the yogurt samples. Simultaneously, we used a commercial strain ( DM8909) as a control strain. We tested the antimicrobial activity of isolates against and by agar spot and well diffusion tests. Then, we tested the antibiotic susceptibility of the 5 strains by using the minimal inhibitory concentration method. We attempted to detect possible bacteriocin genes by PCR sequencing technique. Using a chemically defined medium simulating genital tract secretions, we found that the selected strains could alter the expression of known virulence genes in Bacteriocins derived from these isolated strains had potent antibacterial activity against . and . , with the most effective activity observed in the case of ZX27. In addition, all strains including the . DM8909 were positive for the presence of the plantaricin cluster of genes described in . C11. The tested stains possessed the gene indicating that one of the antibacterial agents was plantaricin. We assume that the production of antimicrobial substances such as bacteriocins induce to upregulate antimicrobial resistance genes. The new isolated strains have bacteriocin-related genes and can change the antimicrobial resistance gene transcription of . .