Lactobacillus plantarum B7 attenuates Salmonella typhimurium infection in mice: preclinical study in vitro and in vivo

Abstract

Abstract Background Salmonella typhimurium is a cause of gastroenteritis including diarrhea. Lactobacillus plantarum is a probiotic widely used to prevent and treat diarrhea. Objectives To determine the protective effects of L. plantarum B7 on diarrhea in mice induced by S. typhimurium. Methods Inhibition of S. typhimurium growth by L. plantarum B7 was determined using an agar spot method. Mice were divided into 3 groups (n = 8 each): a control group, an S group administered 3 × 109 CFU/mL S. typhimurium, and an S + LP group administered 1 × 109 CFU/mL L. plantarum B7 and 3 × 109 CFU/mL S. typhimurium daily for 3 days. Counts of S. typhimurium and percentage of fecal moisture content (%FMC) were determined from stool samples. Serum levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and CXCL1 were determined. Results L. plantarum B7 produced a clear zone on S. typhimurium. There were significantly less S. typhimurium in the feces from mice in the S+LP group than in the S group. Serum levels of TNF-α, IL-6, and CXCL1 in mice from the S group were significantly higher than levels in the S+LP and control groups. Feces from mice in the S group were soft and loose, whereas in the S+LP group they were hard and rod shaped. The %FMC in the S+LP group was significantly less than in the S group. Conclusions L. plantarum B7 can inhibit growth of S. typhimurium, decrease levels of proinflammatory cytokines, and attenuate symptoms of diarrhea induced in mice by S. typhimurium.