B. clausii is a non-pathogenic, Gram-positive bacterium that can temporarily colonize the intestine following oral ingestion . Ianiro et al. performed a systematic review and meta-analysis of randomized controlled trials testing the efficacy of B. clausii in the treatment of childhood diarrhea . They identified 6 randomized controlled trials including 1298 patients and found in their meta-analysis that B. clausii reduced the duration of diarrhea by 9.12 h (95% confidence interval –16.49 to –0.15; Figure 1) and the duration of hospitalization by 0.85 days (–1.56 to –0.15). None of the 6 studies reported serious side effects. Similar findings were obtained in a more recent controlled clinical trial in 65 children .
Fig. 1. Forest plot showing effect of B. clausii on mean duration of diarrhea in a random effect (RE) model. Reproduced with permission from .
Additional clinical and experimental studies support the mechanistic plausibility of the beneficial clinical effects reported in the meta-analysis. In a placebo-controlled study , children with rotavirus infection had lower levels of circulating IgA and increased levels of IgG and IgM compared to children without rotavirus infection. IgA levels increased after treatment and even more after addition of B. clausii, whereas IgG and IgM levels returned closer to healthy values with B. clausii. In vitro studies in Caco-2 cells, a human enterocyte cell line, found that B. clausii protected gut enterocytes against rotavirus-induced decrease in trans-epithelial resistance, apparently by up-regulating the expression of mucin 5AC and the tight junction proteins occludin and zonula occludens-1 . Moreover, B. clausii inhibited reactive oxygen species production and release of the pro-inflammatory cytokines, interleukin-8 and interferon-β in rotavirus-infected cells, and down-regulated pro-inflammatory Toll-like receptor 3 pathway gene expression. Thus, B. clausii has protective effects and stimulates various non-immune mucosal barrier and innate immune system defense mechanisms.
In conclusion, B. clausii is effective and well tolerated in the treatment of childhood diarrhea, apparently by improving intestinal barrier function and innate immunity.
Conflict of interest: M. III Perez and D. M. Greifenberg are employees of Sanofi-Aventis.
Disclosure: Medical writing and publication funded by Sanofi-Aventis Deutschland GmbH.