Bacteroides salyersiae Is a Candidate Probiotic Species with Potential Anti-Colitis Properties in the Human Colon: First Evidence from an In Vivo Mouse Model

Previous studies have indicated a critical role of intestinal bacteria in the pathogenesis of ulcerative colitis (UC). <i>B. salyersiae</i> is a commensal species from the human gut microbiota. However, what effect it has on UC development has not been investigated. In the present study, we explored this issue and demonstrated for the first time that oral administration of <i>B. salyersiae</i> CSP6, a bacterium previously isolated from the fecal sample of a healthy individual, protected against dextran sulfate sodium (DSS)-induced colitis in C57BL/6J mice. In particular, <i>B. salyersiae</i> CSP6 improved mucosal damage and attenuated gut dysbiosis in the colon of DSS-fed mice. Specifically, <i>B. salyersiae</i> CSP6 decreased the population of pathogenic <i>Escherichia-Shigella</i> spp. and increased the abundance of probiotic <i>Dubosiella</i> spp. and <i>Bifidobacterium pseudolongum.</i> Additionally, by reshaping the colonic microbiota, <i>B. salyersiae</i> CSP6 remarkably increased the fecal concentrations of equol, 8-deoxylactucin, and tiglic acid, three beneficial metabolites that have been well documented to exert strong anti-inflammatory effects. Altogether, our study provides novel evidence that <i>B. salyersiae</i> is a candidate probiotic species with potential anti-colitis properties in the human colon, which has applications for the development of next-generation probiotics.