Molecular analysis of Clostridium difficile strains isolated from 18 cases of recurrent clostridium difficile-associated diarrhea.

Recurrence of Clostridium difficile-associated diarrhea (CDAD) occurs in 15 to 20% of patients after discontinuation of treatment. Arbitrarily primed PCR was used to investigate the epidemiology of recurrent CDAD in 18 patients. Reinfection with a new strain occurred in 6 of 18 patients (33.3%), while 12 patients relapsed with the original strain shortly after discontinuation of treatment. These data suggest that reinfection with exogenous C. difficile is a common problem and that not all recurrences are due to relapse.