GRN and clostridium difficile infection: PGRN-deficient mice were highly susceptible to C. difficile using a severe CDI model established with a high dose of 1 × 109 CFUs of C. difficile strain VPI 10,463, whereas others have used a mild CDI model established with a dose of 1 × 108 CFUs of VPI 10,463.31 Furthermore, PGRN supplementation dramatically enhanced the survival of mice in response to severe CDI.