Antimicrobial Effect and Probiotic Potential of Phage Resistant Lactobacillus plantarum and its Interactions with Zoonotic Bacterial Pathogens

Development of phage-resistant probiotic particularly Lactobacillus is an alternative approach to enhance their beneficial effects as in animal feed supplements. In this study, we developed phage-resistant Lactobacillus plantarum (LP(+PR)) mutant and compared their antimicrobial effects and probiotic potential against zoonotic bacterial pathogens including Salmonella enterica serovar Typhimurium, enterohemorrhagic Escherichia coli (EHEC), Staphylococcus aureus, and Listeria monocytogenes with phage-sensitive L. plantarum (LP) strain. LP(+PR) strain showed markedly higher growth rate than wild-type LP strain. In co-culture with LP(+PR) and in the presence of cell-free cultural supernatants (CFCSs) of LP(+PR), the growth of S. Typhimurium, EHEC, S. aureus, and L. monocytogenes were reduced significantly (P < 0.05). The adhesion ability of LP(+PR) was slightly higher than the LP on human epithelial INT-407 cells. Most importantly, LP(+PR) strain significantly inhibited the adhesive and invasive abilities of all four zoonotic pathogens to INT-407 cells (P < 0.05). Moreover, real-time qPCR revealed that in the presence of LP(+PR) strain or its CFCSs, expression of virulence genes of these zoonotic bacterial pathogens were suppressed significantly (P < 0.05). These findings suggest that the LP(+PR) strain is capable of inhibiting major zoonotic bacterial pathogens efficiently and would be a potential candidate for industrial usage in animal production or fermentation.