Oral administration of Lactobacillus plantarum attenuates inflammatory damage in mice challenged with two pathogens

This study aimed to determine the immunomodulatory effect of Lactobacillus plantarum on Salmonella typhimurium and Staphylococcus aureus infection. A mouse inflammation model was established using S. aureus and S. typhimurium. The infected mice were treated with low, medium, and high doses (2 × 108, 4 × 108, and 8 × 108 colony forming units (CFU)/mL, respectively) of three antibacterial L. plantarum strains. The body weight changes, spleen and thymus indexes, cytokines (interleukin (IL)-4 and interferon (IFN)-γ), and secreted immunoglobulin A levels were measured. Compared with the model group, all the L. plantarum-treated groups show increased body weight, reduced spleen swelling, decreased IFN-γ content, significantly increased IL-4 content, and significantly decreased ratio of IFN-γ to IL-4. sIgA levels increased at the end of the experiment. The three L. plantarum strains can effectively attenuate the symptoms of S. typhimurium and S. aureus infection by regulating the Th1/Th2 response and enhancing sIgA secretion.