Animal experiment: the effect of B. fragilis on gut microbiota in AAD rats

Antibiotic-associated diarrhea (AAD) is characterized by the disruption of the gut microbiota. Accordingly, probiotics are routinely used to treat AAD, but the effectiveness of this treatment and the mechanisms by which probiotics alleviate symptoms remain poorly clarified. In this study, we demonstrated that rats exposed to adequate antibiotics developed diarrhea symptoms and exhibited microbiota alterations with overgrowth of some pathogenic bacteria. Oral treatment with B. fragilis ameliorated AAD-related diarrhea symptoms and reversed specific microbial changes in AAD rats by increasing some commensal microbiota.