A novel taurine-respiring murine gut bacterium contributes to colonization resistance against enteropathogens

Taurine-respiring gut bacteria produce H2S with ambivalent impact on host health. We report the isolation and genomic-ecophysiological characterization of the first taurine-respiring mouse gut bacterium.Taurinivorans murisrepresents a new widespread species with protective capacity against pathogens and differs from the human gut sulfidogenBilophila wadsworthiain its sulfur metabolism and host distribution. Despite alternative physiologies, taurine respiration was the mainin vivolifestyle ofT. murisindependent of mouse diet and genotype. In gnotobiotic mice,T. murisselectively enhanced the activity of a sulfur metabolism gene-encoding prophage and provided slightly increased colonization resistance againstSalmonellaTyphimurium, which showed reduced expression of galactonate catabolism genes. We identifiedT. murisas the dominant sulfidogen of a mouse microbiota that conferred H2S-mediated protection againstKlebsiella pneumoniaein a previous study. Together, we revealed the realized physiological niche of a key murine gut sulfidogen and its impact on pathogen and phage gene expression.One sentence summaryOur work identified and characterized a new core member of the murine gut microbiota, revealed sulfidogenic taurine respiration as its predominantin vivolifestyle, and emphasizes its protective function in pathogen colonization.