Probiotic therapy for the prevention and treatment of Clostridium difficile-associated diarrhea: a systematic review.

BACKGROUND The recent increase in the number and severity of cases of nosocomial Clostridium difficile-associated diarrhea (CDAD) has prompted interest in the use of probiotics for the prevention and treatment of this disease. We performed a systematic review of randomized controlled trials to assess the effectiveness of probiotic therapy. METHODS We searched the PubMed, EMBASE, INAHTA, HEN and Cochrane Collaboration databases to identify trials in which the prevention or treatment of CDAD with probiotic therapy was the primary or secondary outcome. We extracted data on the number of patients randomly assigned to receive probiotic or placebo, the number of patients with CDAD, the type of probiotic, criteria for diagnosing CDAD, persistence of infection after treatment, compliance and adverse effects. RESULTS We identified 4 eligible studies in which prevention (n = 1) or treatment (n = 3) of CDAD was the primary outcome. The benefit of probiotic therapy seen in 2 of the studies was restricted to subgroups characterized by severe CDAD and increased use of vancomycin. The remaining 2 studies were too methodologically flawed for us to draw meaningful conclusions. We also identified 4 trials in which prevention of antibiotic-associated diarrhea with probiotics was the primary outcome and prevention of CDAD a secondary outcome. These studies were limited primarily by too few CDAD cases and provided no evidence of effective prophylaxis. Overall, heterogeneity in choice and dose of probiotic and in criteria for diagnosing CDAD makes it difficult to synthesize information from the 8 studies. INTERPRETATION Studies conducted to date provide insufficient evidence for the routine clinical use of probiotics to prevent or treat CDAD. Better designed and larger studies are needed.