Probiotic Protects Against Pathogens

Researchers from University College Cork, Cork, Ireland recently investigated the potential of using a probiotic bacteria to protect against Listeria monocytogenes. The results of this research were published in the May 1 issue of the Proceedings of the National Academy of Sciences.

The study involved testing the effectiveness of Lactobacillus salivarius UCC118 in protecting mice from Listeria infection. The mice were exposed to two different strains of Listeria, EGDe and LO28. The probiotic provided protection against infection due to a bacteriocin produced by the probiotic. A stable mutant of Lb. salivarius UCC118 that is unable to produce the Abp118 bacteriocin also failed to protect mice against infection with two strains of L. monocytogenes, EGDe and LO28, confirming that bacteriocin production is the primary mediator of protection against this organism, note the researchers. Furthermore, Lb. salivarius UCC118 did not offer any protection when mice were infected with a strain of L. monocytogenes expressing the cognate Abp118 immunity protein AbpIM, confirming that the antimicrobial effect is a result of direct antagonism between Lb. salivarius and the pathogen, mediated by the bacteriocin Abp118.

These results led the researchers to suggest that the results of the UCC work clearly demonstrate a role for bacteriocins in protecting the host against potentially lethal infections, as noted in a press release from the university. The study is the first to clearly demonstrate a mechanism by which probiotic bacteria may act to help improve the health of consumers.