Annual Probability of C. diff Infection

Clostridioides difficile (C. diff) causes approximately 500,000 infections and 29,000 deaths in the United States each year, making it the most common healthcare-associated infection. The annual incidence is approximately 150 per 100,000 population. C. diff is classified by the CDC as an "urgent" antimicrobial resistance threat.

C. diff infection typically occurs after antibiotic use disrupts the normal gut microbiome, allowing C. diff bacteria to proliferate and produce toxins that cause inflammation of the colon. The most commonly implicated antibiotics include fluoroquinolones, clindamycin, cephalosporins, and broad-spectrum penicillins. Risk factors include recent antibiotic use (the strongest risk factor), hospitalization, age over 65, immunosuppression, and previous C. diff infection.

Recurrence is a major challenge: about 25% of patients have a recurrence after initial treatment, and the risk increases with each subsequent episode. Treatment includes oral vancomycin or fidaxomicin for initial episodes. For recurrent C. diff, fecal microbiota transplantation (FMT) has shown cure rates of 80-90% and is increasingly recognized as a breakthrough treatment. The FDA approved the first FMT-based product (REBYOTA) in 2022.