Evaluation of antagonistic effect of probiotics Bifidobacteria spp. on E.coli O157:H7 in vitro

E. coli O157:H7 is recognized to be one of the most important food-born pathogens causing hemolytic uremic syndrome (HUS). The purpose of this study was to evaluate the effects of probiotics Bifidobacteria spp. against growth or activity of E.coli O157:H7 was used in vitro.

This experimentally study was performed on strains isolated from clinical samples and standard E. coli O157:H7. All samples were enriched on BHI and TSA media and then, cultured on CT-SMAC. For confirmation of verotoxigenic E. coli, biochemical, serological testes, multiplex PCR and culture on Vero cell line were performed. Also, agar gel diffusion assay was used to detect the antagonistic activity of the probiotic bacteria against pathogenic bacteria.

According to used amount of probiotic, all the investigated strains showed a 15-30 diameter blanked area on Shiga producer E. coli O157:H7. The effect has been repeated in neutral pH, while organic acids had any meaningful effects on the pathogen strains.

Probiotics are able to inhibit growth of E.coli O157:H7 and it’s not only because of organic acid or low pH but also it’s because of produce other antibacterial agents.