Infection of Hamsters with Epidemiologically Important Strains ofClostridium difficile

Abstract

Five different toxigenic strains of Clostridium difficile of known human epidemiologic importance were tested for virulence in hamsters. Three strains—types B1, J9, and K14—have caused hospital outbreaks. Type Y2 is associated with a high rate of asymptomatic colonization in patients. The fifth strain, type CF2, is a toxin A–negative, toxin B–positive strain implicated in multiple human cases of C. difficile–associated diarrhea. Groups of 10 hamsters per strain were given 1 dose of clindamycin, followed 5 days later with gastric inoculation of 100 cfu of C. difficile. Hamsters given types B1, J9, K14, or Y2 showed 90%–100% colonization (albeit at a slower rate with type Y2) and 100% mortality of colonized animals. Hamsters challenged with type CF2 showed 60% (P=.01) colonization and 30% mortality (P=.0003). The hamster model demonstrated pathogenicity differences between a toxin variant strain and standard toxigenic strains but no significant differences among the standard strains