A Mouse Model of Clostridium difficile-Associated Disease

Background & Aims: Infection with Clostridium difficile causes nosocomial antibiotic-associated diarrhea and colitis. Hamsters historically have been used to investigate disease pathogenesis and treatment, but are not ideal models because of the lack of hamster-specific reagents and genetically modified animals, and because they develop fulminant disease. The aim of this study was to establish a mouse model of antibiotic-induced C difficile-associated disease (CDAD) that more closely resembles human disease. Methods: C57BL/6 mice were exposed to a mixture of antibiotics (kanamycin, gentamicin, colistin, metronidazole, and vancomycin) for 3 days. Two days later, they were given injections of clindamycin and then challenged 1 day later with different doses of C difficile. Results: Mice that were exposed to antibiotics and then challenged with C difficile developed diarrhea and lost weight. Disease severity varied from fulminant to minimal in accordance with the challenge dose. Typical histologic features of CDAD were evident. Oral vancomycin prevented CDAD in all mice, but 68% died from colitis after treatment was discontinued. All animals that survived an initial episode of CDAD showed no evidence of diarrhea or colitis after subsequent rechallenge with C difficile. Different strains of C difficile tested in the model showed different levels of virulence in mice. Conclusions: We have developed a mouse model of CDAD that closely represents the human disease. in light of the recent substantial increases in CDAD incidence and severity, this model will be valuable in testing new treatments, examining disease pathogenesis, and elucidating mechanisms of protective immunity.