Which treatment is used for C. difficile infection and may have lower recurrence rates in some strains?

• A. Fidaxomicin
• B. Metronidazole
• C. Vancomycin
• D. Rifaximin

Answer: (A)

The main idea is selecting a CDI treatment that not only clears the infection but also lowers the chance of coming back by sparing the normal gut flora. Fidaxomicin fits this well: it is a narrow-spectrum antibiotic that concentrates in the colon where C. difficile resides, with minimal systemic absorption, so it preserves other gut bacteria. This microbiota-sparing effect helps reduce recurrence, and clinical studies have shown fidaxomicin has lower relapse rates than vancomycin in many strains, especially non-hypervirulent ones. Metronidazole and vancomycin are effective but tend to have higher recurrence rates, and rifaximin is not typically used as first-line therapy for initial CDI. So fidaxomicin is the best choice when aiming for a lower chance of recurrence across strains.