Vancomycin vs. Nitazoxanide to Treat Recurrent C. Difficile Colitis

Inclusion Criteria: * Patients \>18 years of age * clinical diagnosis of C. difficile associated disease, based on the new onset of diarrhea, abdominal discomfort, or otherwise unexplained fever or leukocytosis * diagnosis of C. difficile colitis proven by positive assay for C. difficile toxin in feces * disease has been treated, and the symptoms failed to respond to treatment with metronidazole, or symptoms recurred after the patient has completed a course of metronidazole therapy * able to take oral medication Exclusion Criteria: * patients with other recognized causes of diarrhea or colitis * women of child bearing age who are pregnant, breast feeding, or not using birth control * patients of known causes of diarrhea, such as inflammatory bowel disease * patients in whom diarrhea can not be evaluated, such as those with colostomy * patients with renal insufficiency (BUN or creatinine \>3.0 times baseline) * patients who are medically unstable, for example in an ICU and on medications to maintain blood pressure * patients who are regarded as unlikely to survive for 3 months