Alleviative effects of Bacillus coagulansstrains on IBS-unraveling strain specificity through physiological and genomic analysis

The high intraspecies heterogeneity of Baciillus coagulansleads to significant phenotypic differences among different strains. Thus, 6 B. coagulansstrains were tested in the present study using an irritable bowel syndrome (IBS) animal model to determine whether the IBS-alleviating effects of B. coagulansstrains are strain-specific. The results of this study showed that the ingestion of B. coagulansGBI-30, 6086, and B. coagulansCCFM1041 significantly alleviated IBS symptoms in mice. In contrast, other B. coagulansstrains showed no or limited alleviating effects on IBS symptoms. According to our experimental results, the two main common features of these strains were as follows: 1) The resistance of vegetative cells to bile salts, and 2) ability to synthesize specific lipids and secondary metabolites. Screening strains based on these two indicators may greatly reduce costs and provide a basis for mining new functional B. coagulansstrains. Our results also suggest that administration of B. coagulanscould significantly regulate microbiota dysbiosis in animal models. Moreover, the close relationships between the gut microbiota, gut microbiota metabolites, and IBS were further confirmed in this study.