Which antibiotic is an appropriate option for treating Clostridioides difficile infection?

• A. Amoxicillin
• B. Oral vancomycin
• C. IV Metronidazole
• D. Clindamycin

Answer: (B)

Treating Clostridioides difficile infection relies on delivering the antibiotic directly to the colon where the bacteria reside, while minimizing systemic absorption. Oral vancomycin fits this requirement because it stays within the GI tract, achieving high concentrations in the stool to effectively eradicate C. difficile and its toxin production.

Amoxicillin and clindamycin are actually antibiotics that can disrupt normal gut flora and predispose to CDI; they’re not therapies for active C. difficile infection. Metronidazole used to be used for mild disease, but it’s now less effective than oral vancomycin or fidaxomicin and may fail more often, and intravenous metronidazole doesn’t provide adequate colonic concentrations. Therefore, oral vancomycin is the preferred option among these choices, with fidaxomicin also available as an alternative in some cases.