Antibiotic treatment disturbs the normal gastrointestinal flora and raises risk for Clostridium difficile–associated diarrhea (CDAD). To evaluate the effectiveness and safety of probiotics for preventing CDAD, researchers performed a systematic review and meta-analysis. CDAD was defined as an episode of diarrhea associated with a positive C. difficile culture or toxin assay.
Twenty randomized, controlled trials that involved 3818 adults and children were included in the analysis; 18 studies were placebo controlled. Information on antibiotic regimens was not provided. Probiotics used in the trials included Bifidobacterium, Lactobacillus, Saccharomyces, and Streptococcus species.
Probiotics lowered the incidence of CDAD by approximately 66%. The incidence of adverse events, including abdominal cramping, nausea, fever and flatulence, was higher among controls than among probiotic recipients (12.6% vs. 9.3%); no serious adverse events were attributed to probiotics. The results were similar among children and adults, with lower and higher doses of probiotics, and across the different probiotic species.
Comment: The authors believe that their meta-analysis provides moderate-quality evidence to support a clinically significant protective effect of probiotics in preventing C. difficile–associated diarrhea. As with any meta-analysis, the quality of individual studies varied; the grading methodology used in this analysis required a larger sample size for the evidence to be considered high quality. Nevertheless, given the lack of serious adverse events, we might reasonably encourage use of probiotics, particularly for susceptible patients, such as those who are receiving broad-spectrum antibiotics.