Recurrent pseudomembranous colitis unassociated with prior antibiotic therapy.

Fulminant and recurring pseudomembranous colitis developed in an elderly woman without prior antibiotic administration within the previous year. Stool culture yielded Clostridium difficile, and tissue cultures showed C difficile cytotoxin. Treatment with vancomycin hydrochloride was initially successful, but a serious relapse after its discontinuation necessitated low-dose long-term prophylaxis. Clostridium difficile may be responsible for pseudomembranous colitis unassociated with antibiotic therapy.