- Severe and/or complicated CDI (Severe: white blood cell count ≥15 × 10³/μL and/or an increase in creatinine ≥1.5 times the baseline level; complicated: at least 1 of the following: hypotension requiring vasopressors, ICU admission for a complication of CDI, ileus leading to installation of a nasogastric tube, toxic megacolon, colonic perforation, or colectomy)