Protective Effect of 1Z, Isolated From Brazilian Kefir, Against Serovar Typhimurium in Experimental Murine Models.

Kefir is a beverage obtained by fermentation of milk or sugar solution by lactic acid bacteria and yeasts, and several health benefits have been attributed to its ingestion, part of them being attributed to species. The objective of the present study was to evaluate, , the probiotic potential of 1Z, isolated from Brazilian kefir grains. Initially, conventional mice were orally treated daily or not during 10 days with a suspension of 1Z, and then orally challenged with serovar Typhimurium. Treatment with 1Z resulted in higher survival (70%) of animals after the challenge with the pathogen than for not treated mice (0%). When germ-free mice were monoassociated (GN-PS group) or not (GN-CS group) with 1Z and challenged after 7 days with Typhimurium, fecal counts were significantly lower ( < 0.05) for the GN-PS group when compared to the GN-CS group. Histopathological analysis revealed less damage to the ileum mucosa, as demonstrated by smallest perimeter of major lesions for mice of the GN-PS group in comparison to the group GN-CS ( < 0.05). These findings were accompanied by a lower expression of IFN-γ and TNF-α in the intestinal tissue of GN-PS mice. Additionally, translocation of Typhimurium to liver was significantly lower in GN-PS than in GN-CS mice ( < 0.05), and IgA levels in intestinal content and number of Kupffer cells in liver were higher. No difference was observed for hepatic cellularity between GN-PS and GN-CS groups ( > 0.05), but the pattern of inflammatory cells present in the liver was predominantly of polymorphonuclear in GN-CS group and of mononuclear in the GN-PS group, and a higher hepatic expression of IL-10 and TGF-β was observed in GN-PS group. Concluding, 1Z showed to be a potential probiotic strain that protected mice from death after challenge with Typhimurium, apparently by immunological modulation.