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 muris represents a new widespread species with protective capacity against pathogens and differs from the human gut sulfidogen Bilophila wadsworthia in its sulfur metabolism and host distribution. Despite alternative physiologies, taurine respiration was the main in vivo lifestyle of T. muris independent of mouse diet and genotype. In gnotobiotic mice, T. muris selectively enhanced the activity of a sulfur metabolism gene-encoding prophage and provided slightly increased colonization resistance against Salmonella Typhimurium, which showed reduced expression of galactonate catabolism genes. We identified T. muris as the dominant sulfidogen of a mouse microbiota that conferred H2S-mediated protection against Klebsiella pneumoniae in 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 predominant in vivo lifestyle, and emphasizes its protective function in pathogen colonization.