For a patient suspected to have C. difficile infection based on diarrhea and previous antibiotic use, what is the recommended treatment?

The recommended treatment for suspected Clostridioides difficile (C. difficile) infection in adults, particularly following antibiotic use, is oral vancomycin. This approach is supported by clinical guidelines due to its effectiveness in eliminating the C. difficile bacteria from the gastrointestinal tract.

Oral vancomycin is the preferred choice because it directly targets the pathogen within the gut, and systemic absorption is minimal, thus allowing high levels to be maintained within the intestinal lumen where C. difficile causes infection. It's generally administered for a duration of 10 days, aligning with recommendations for treating moderate to severe cases.

While metronidazole has historically been utilized, recent guidelines suggest prioritizing oral vancomycin given its superior efficacy, particularly in severe cases or recurrent infections. Fidaxomicin, though effective, is often reserved for specific situations due to its higher cost and is not administered intravenously as it is only available in oral formulation. Vancomycin administered intravenously does not achieve adequate concentrations in the gut to treat C. difficile infections effectively.

Thus, oral vancomycin is the most appropriate and widely endorsed treatment for managing a suspected C. difficile infection in this context.