Probiotics are used to treat and prevent a variety of conditions. One area in which probiotics have tremendous potential is the prevention of antibiotic-associated diarrhea (AAD). AAD can occur in up to 25% of patients receiving antibiotics, and of these, 25% may develop Clostridium difficile infection.1 This infection can be severe, may require hospitalization, and is associated with increased health care costs. Given the variety of probiotic preparations and the variability in study designs, systematic reviews often are used to evaluate probiotic studies. Several recent systematic reviews have provided additional evaluation of probiotics for preventing AAD.2–4
Susanne Hempel, PhD, and colleagues2 published an analysis of 63 studies with 11,811 patients. The study included trials in both inpatients and outpatients and enrolled adults and children. Various probiotic preparations were used, and the most common indication for antibiotics was Helicobacter pylori eradication. Lactobacilli (either alone or in combination with other organisms), Bifidobacterium, and the yeast Saccharomyces boulardii were the most common strains used. The pooled analysis revealed a significant reduction of 42% in development of AAD in patients receiving versus not receiving probiotics (relative risk [RR] 0.58 [95% CI 0.50–0.68], P = 0.001). In 14 trials that reported testing for C. difficile infection, risk of infection was significantly reduced by 71% in those using a probiotic (0.29 [0.17–0.48], P < 0.001). No major adverse effects related to probiotics were reported.
Another systematic review by Bradley C. Johnston, PhD, and colleagues3 specifically addressing C. difficile infection included 20 trials with 3,818 patients, with a mix of inpatients and outpatients. Lactobacilli and S. boulardii were the most common strains used. Probiotics significantly reduced the incidence of C. difficile infection by 66% (RR 0.34 [95% CI 0.24–0.49]). The subgroup that received greater than 10 billion colony-forming units (CFUs) of probiotics per day had significantly greater efficacy than those receiving less than 10 billion CFUs per day. Both adults and children were found to have similar results, and no major adverse effects were reported.
The most recent systematic Cochrane review regarding probiotics for preventing AAD was published in May 2013 and included 23 trials in 4,492 patients (adults and children). Lactobacilli and S. boulardii were the most common strains used. The results revealed a significant 64% reduction in the incidence of C. difficile–associated diarrhea (RR 0.36 [95% CI 0.26–0.51]) in patients receiving compared with those not receiving probiotics. However, the actual incidence of C. difficile infection was not reduced (0.89 [0.64–1.24]).
The results from these recent reviews suggest that probiotics are generally effective in reducing the incidence of AAD and C. difficile infection in both children and adults. For patients receiving antibiotics, use of adjunctive probiotics can be considered. As with any adjunctive therapy, safety and added cost are important considerations. In general, probiotics are considered safe; however, they should be avoided in immunocompromised or debilitated patients because of the potential for infection in these populations.4,5 Based on these studies, products containing Lactobacilli alone or in combination with other species can be considered a first-line option, while products containing S. boulardii also can be used. Patients should separate their probiotics from their antibiotic doses to avoid reductions in probiotic efficacy. Patients also should be educated to report severe or persistent diarrhea while receiving antibiotics, as AAD and C. difficile infection remain possible even with the use of probiotic preparations.