MYD88 and clostridium difficile infection: To determine intra-strain type virulence diversity, we used an antibiotic-treated mouse model of CDI to test a panel of PaLoc- and CdtLoc-encoding ST1 C. difficile clinical isolates to quantify disease severity.20 Clinical C. difficile isolates with identical PaLocs caused a range of disease severities, with two isolates causing no detectable disease in antibiotic-treated wild-type, germ-free mice or MyD88-deficient mice.