Nancy Toedter Williams


Am J Health Syst Pharm. 2010;67(6):449-458. 

In This Article

AAD and C. Difficile Infection

There is evidence that probiotics can prevent AAD and treat C. difficile infection (CDI); however, data are conflicting or inconclusive.[2,5,13,14,17] The most common probiotic microorganisms used for these diseases include lactobacilli and S. boulardii.[5] Two meta-analyses of studies examining the use of probiotics to prevent AAD suggested that concurrent administration of probiotics (most commonly lactobacilli and S. boulardii) with antibiotics resulted in a reduced frequency of diarrhea.[28,29] The first meta-analysis, which examined 7 trials (n = 881), revealed a combined relative risk (RR) of 0.3966 (95% CI, 0.27–0.57) in favor of a beneficial effect of probiotics for reducing the risk of AAD.[28] The other meta-analysis yielded a combined odds ratio of 0.37 (95% CI, 0.26–0.53; p < 0.001) for pooled data from all 9 trials (n = 1214), supporting probiotic treatment over placebo in the prevention of AAD.[29]

A third meta-analysis reviewed 25 randomized controlled trials (n = 2810) examining the use of probiotics for the prevention of AAD and 6 randomized controlled trials (n = 354) of probiotic therapy for the treatment or prevention of CDI.[30] The meta-analysis revealed that LGG, S. boulardii, and various mixtures of two probiotic strains significantly reduced the frequency of AAD. However, only S. boulardii in combination with oral vancomycin or metronidazole or both significantly decreased the recurrence of CDI. Other probiotics tested, including LGG and Lactobacillus plantarum 299v in combination with oral vancomycin or metronidazole, were not effective in decreasing CDI recurrence rates. On the other hand, a recent study found that the rate of C. difficile colonization in 44 critically ill patients receiving antibiotics was significantly reduced by enteral administration of L. plantarum 299v (p < 0.05).[31] It is important to note that this study was stopped prematurely due to the low rate of enrollment and reduced funding.

In contrast to the previous studies that found that probiotics reduced the rate of CDI, a systematic review of 8 randomized controlled trials did not find sufficient evidence for routine probiotic use in CDI.[32] A Cochrane Library review also concluded that there was inadequate evidence to support the adjunctive use of probiotics for CDI.[33] While results have been inconsistent, some studies have indicated that probiotics, especially S. boulardii, may prevent C. difficile overgrowth and decrease CDI recurrence.


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