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

Abstract

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