Antagonism toward the intestinal microbiota and its effect onVibrio choleraevirulence

Abstract

The bacterial Type VI secretion system (T6SS) is a nano-machine that delivers toxic effector proteins into target cells killing them. Here we show that the V. cholerae T6SS attacks members of the host commensal microbiota in vivo , facilitating the pathogen’s colonization of the murine gut. This microbial antagonistic interaction drives measurable changes in the pathogenicity of V. cholerae through enhanced intestinal colonization, expression of bacterial virulence genes, and activation of host innate immune genes. Because ablation of mouse commensals by this enteric pathogen correlated with more severe diarrheal symptoms, we conclude that antagonism toward the gut microbiota could improve the fitness of V. cholerae as a pathogen by elevating its transmission to new susceptible hosts. Type 6 secretion-mediated killing of gut commensal microorganisms enhances virulence of Vibrio cholera and modulates host gene expression