Lactobacillus rhamnosus V5 Prevents Salmonella enterica Serovar Typhimurium Invasion in Cell Culture and Mice Infection

Aims: The aim of this study was to evaluate the protective capacity of the exopolysaccharide-producing Lactobacillus rhamnosus V5 against invasion in vitro and in vivo with S. typhimurium.

Methodology: We tested the antimicrobial activity of the compound extracted from the lactobacilli against S. typhimurium directly, also we tested the interference of this compound in S. typhimurium adherence and invasion of HeLa and HEp-2 cells (in vitro testings). For in vivo experiments, we used 16 BALB/c female mice. Through gavage method we introduced L. rhamnosus as probiotic and then infected mice with S. enterica serovar typhimurium. After euthanasia, spleen, liver and Peyer's patches removed for microbiological and histopathological analysis.

Results: The results showed that lactobacilli were able to produce antimicrobial compounds against S. typhimurium. These lactobacilli inhibited the adhesion and invasion of S. typhimurium in HeLa and HEp-2 cells, respectively. The challenge assay in the murine model demonstrated a decrease in pathogen translocation in the spleen and liver from mice treated with probiotic as well as protection of ileal tissue in lactobacilli-treated mice. The histopathological analysis demonstrated the presence of prominent lymphoid nodules in the ileum from the non-treated lactobacilli mice.

Conclusion: Our results suggest that L. rhamnosus improved the effectiveness of the intestinal barrier and, thus, could be a potential probiotic to control salmonellosis.