Infection of hamsters with epidemiologically important strains of Clostridium difficile

Five different toxigenic strains of Clostridium difficile of known human ep idemiologic importance were tested for virulence in hamsters. Three strains -types B1, J9, and K14-have caused hospital outbreaks. Type Y2 is associate d with a high rate of asymptomatic colonization in patients. The fifth stra in, type CF2, is a toxin A-negative, toxin B-positive strain implicated in multiple human cases of C. difficile-associated diarrhea. Groups of 10 hams ters per strain were given 1 dose of clindamycin, followed 5 days later wit h 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 t ype Y2) and 100% mortality of colonized animals. Hamsters challenged with t ype CF2 showed 60% (P = .01) colonization and 30% mortality ( P = .0003). T he hamster model demonstrated pathogenicity differences between a toxin var iant strain and standard toxigenic strains but no significant differences a mong the standard strains.