Lactate-utilizing bacteria ameliorates DSS-induced colitis in mice.

Inflammatory bowel diseases (IBD) stem from alterations in the intestinal immune system and microbial dysbiosis, but the precise interactions between bacteria and IBD remain obscure. The commensal microbiota have a profound impact on human health and diseases. Here, we developed a selective culture medium for lactate-utilizing bacteria (LUB) that function as candidate probiotics to ameliorate IBD using a mouse model. Firstly, LUB, including Megasphaera, were enriched from human faeces using a selective medium with lactate. LUB efficiently attenuated the pathology of colitis induced by dextran sulphate sodium (DSS). Next, LUB administration counteracted the dysbiosis associated with the intestinal inflammatory process, and elevated the proportion of Escherichia-Shigella in intestines. Moreover, E. coli isolated from healthy faeces downstream recapitulated lactate-utilizing bacterial community to ameliorate the severity of DSS-induced acute colitis. In conclusion, our finding revealed that LUB were sufficient to exert inflammatory protection against colitis in mice, highlighting a novel therapeutic strategy to use LUB as potentially curable probiotics for therapeutic manipulation for IBD.