The trials were of varying quality, had considerable heterogeneity and involved 766 children who were taking antibiotics. Overall, compared with placebo, probiotics reduced the incidence of diarrhoea from 28.5% to 11.9%. Thus, for every six or seven children taking antibiotics, probiotics would prevent one child from developing antibiotic-associated diarrhoea.

Lactobacillus GG, Saccharomyces boulardii and a combination of Bifidobacterium lactis and Streptococcus thermophilus were the most effective probiotic strains; Lactobacillus acidophilus with either Bifidobacterium infantis or Lactobacillus bulgaricus did not significantly reduce the risk for antibiotic-associated diarrhoea.

The data were insufficient to allow conclusions about the effects of probiotics in preventing Clostridium difficile diarrhoea or diarrhoea from specific antibiotic classes. No adverse effects were reported.

Comment: The finding that probiotics are effective in preventing antibiotic associated diarrhoea among children is consistent with results from previous systematic reviews of trials that included adults. Because these trials involved different probiotic strains and doses, more data are needed to determine how to use probiotics optimally. Until then, it seems reasonable to recommend probiotics for children prone to antibiotic-associated diarrhoea.

Reference: Szajewska H, et al. Probiotics in the prevention of antibiotic-associated diarrhea in children: a meta-analysis of randomized controlled trials. J Pediatr 2006; 149:367-372.