TLR5 and clostridium difficile infection: According to this role of C. difficile flagella, analysis of the CDI elicited by R20291 and 630Δerm C. difficile strains in the tlr5−/− KO mice, which do not express TLR5 in the intestinal mucosa, strengthens the role of the TLR5-related flagellar signaling in the pathogenesis of C. difficile.