Protective Effect of <i>Lactiplantibacillus plantarum</i> ZDY2013 against <i>Salmonella</i> Typhimurium Infection

Probiotics are critical for resisting the colonization of foodborne pathogens in gut. <i>Lactiplantibacillus plantarum</i> 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 <i>L. plantarum</i> ZDY2013 on <i>Salmonella enterica</i> 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 <i>L. plantarum</i> ZDY2013 could effectively reduce the <i>Salmonella</i> 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, <i>L. plantarum</i> ZDY2013 could significantly reduce the adhesion and invasion of <i>S.</i> Typhimurium to HT-29 epithelial cells, activate macrophages and enhance its bactericidal ability. These results indicated that live and heat-killed <i>L. plantarum</i> ZDY2013 has the potential to be developed as a functional health food against <i>S</i>. Typhimurium infection.