MYD88 and colitis: To further investigate this avirulent phenotype, we inoculated ST1-75 into MyD88−/− mice, which lack the adaptor protein for Toll-like receptor signaling.24MyD88−/− mice fail to recruit neutrophils to the colonic tissue during early stages of CDI and display markedly increased susceptibility to C. difficile-induced colitis.25 Here, MyD88−/− mice were treated with antibiotics and infected with either ST1-75 or R20291.