Inhibitory effect of Lactobacilli (Isolated from Tarkhineh Dough) on E.coli and Lis.monocytogenes colonization
International Journal of Biosciences
Lactobacilli are the most widely used probiotics that can inhibit the attachment of pathogenic bacteria through colonization and adhesion to epithelial cells or producing inhibitory compounds. In this study, we aimed to evaluate adhesion ability of Lactobacillus isolated from Tarkhineh Dough to Caco-2 cells in presence or absence of food-born pathogenic bacteria like E.coli and Lis.monocytogenes. In addition, we studied inhibitory effects of these isolates on above pathogenic bacteria. 16
... bacteria. 16 strains of Lactobacillus isolates were grown under anaerobic conditions at 37 o C for 24h. The Caco-2 cells were used in assay of Lactobacillus isolates adhesion. The inhibitory effects of these strains against E.coli and Lis. monocytogenes, were evaluated by diffusion method through measuring the ability of Caco-2 cells for adhesion or production of inhibitory compounds. TD16 showed the strongest attachment among the other isolates with more than 2×10 4 CFU/Well. In a competitive inhibition assay, TD3, TD4, TD12, and TD16 strains indicated more than 50% inhibitory effect on adhesion ability of E.coli and Lis. monocytogenes to Caco-2 cells. TD7 and TD14 revealed similar effects on attachment of Lis. monocytogenes. Moreover, the antagonist effects of Lactobacillus isolates which analysed through well diffusion method showed that TD5 had the strongest inhibitory effect on Lis. monocytogenes while TD3 and TD6 had the highest inhibitory effect on E. coli. Production of antimicrobial compounds like bacteriocin may be related to the inhibitory effects of Lactobacillus isolates against pathogenic bacteria, so application of probiotic strains such as Lactobacilli can be one of the therapeutic approaches in bacterial infections.