Vancomycin for the treatment of Clostridium difficile Infection: for whom is this expensive bullet really magic?

The epidemiology, clinical severity, and case-fatality ratio of Clostridium difficile infection (CDI) changed dramatically with the emergence of a toxin hyperproducing strain (BI/NAP1/027) in North America and Europe in 2000. For the treatment of CDI, metronidazole and vancomycin remain the 2 most commonly used drugs. The 3 randomized controlled trials published thus far, as well as the upcoming tolevamer trial, use intermediate outcomes, rather than the outcomes that now preoccupy clinicians: the frequency of complications or recurrence. The major advantage of metronidazole is its low price. The major advantage of orally administered vancomycin is its more favorable pharmacokinetics. Facilitating vancomycin-resistant enterococci colonization and/or infection is a potential drawback of both drugs. Pending the development of a prospectively validated scoring system, members of the Infectious Diseases Society of America/Society for Healthcare Epidemiology of America expert committee will define severe CDI as present in any patient with a leukocyte count > or =15,000 cells/mm(3) or a creatinine level increased by > or =50% from baseline. For patients with mild-to-moderate CDI (defined by a leukocyte count <15000 cells/mm(3) and a creatinine level <1.5 times the baseline value), there is no evidence that treatment with vancomycin is superior to treatment with metronidazole (even for intermediate outcomes), and metronidazole therapy should be preferred. For patients with severe CDI who are not infected with BI/NAP1/027, there is reasonable evidence that the better pharmacokinetics of vancomycin translate into a lower probability of complications. For those patients who are infected with BI/NAP1/027, the superiority of vancomycin therapy remains to be proven. In practice, because it is not yet possible to rapidly type the strains, all patients with severe CDI should be treated with vancomycin. Future trials should use complicated CDI and recurrences as their primary outcomes.