Protective Effect of Lactiplantibacillus plantarum ZDY2013 against Salmonella Typhimurium Infection

Probiotics are critical for resisting the colonization of foodborne pathogens in gut. Lactiplantibacillus plantarum ZDY2013 has been proven to have multiple biological activities, including antagonizing pathogens. In this study, we systematically evaluated the protective effects of live and heat-killed L. plantarum ZDY2013 on Salmonella enterica serotype Typhimurium infection and investigated the potential mechanisms using mice infection model, HT-29 epithelial cell model, and RAW264.7 macrophage model. The results showed that live and heat-killed L. plantarum ZDY2013 could effectively reduce the Salmonella load in mice, improve the intestinal barrier by upregulating the expression of tight junction proteins (Zonula occludens protein 1 and Claudin-1) and the number of goblet cells, and alleviate the inflammation by decreasing the level of proinflammatory cytokines (interleukin-1β, tumor necrosis factor-α, interferon gamma and IL-6). In addition, L. plantarum ZDY2013 could significantly reduce the adhesion and invasion of S. Typhimurium to HT-29 epithelial cells, activate macrophages and enhance its bactericidal ability. These results indicated that live and heat-killed L. plantarum ZDY2013 has the potential to be developed as a functional health food against S. Typhimurium infection.