Which treatment is considered first-line for severe Clostridium difficile infection?

Vancomycin is recognized as the first-line treatment for severe Clostridium difficile infection (CDI). This is due to its effectiveness and positive clinical outcomes in managing severe cases of CDI, particularly those characterized by complications such as pseudomembranous colitis or recurrent infections. Vancomycin is administered orally as it achieves high concentrations in the gastrointestinal tract, which is critical for treating localized infections.

In the context of CDI, guidelines recommend vancomycin as the preferred option because it has been shown to have lower rates of treatment failure and recurrence compared to other agents. Metronidazole, while previously used for non-severe CDI and still applicable in certain cases, is no longer preferred for severe infections due to concerns about its inferior effectiveness. Azithromycin and fluoroquinolones are not suitable first-line treatments for CDI and are not typically used in this context due to their lack of demonstrated efficacy against C. difficile. Thus, vancomycin is the most appropriate choice for treating severe CDI.