Effects of antibiotic therapy on the gastrointestinal microbiota and the influence of Lactobacillus casei

Aims of methods Effects of intervention with Lactobacillus casei Shirota (LcS) on the incidence of antibiotic-associated diarrhoea (AAD), Clostridium difficile infection (CDI) and changes in faecal microbiota were analysed using C. difficile ELISA (678 patients), qPCR using 16S rRNA group-specific primers, C. difficile-toxin kit and polymerase chain reaction/denaturing gradient gel electrophoresis (56 patients). Results As much as 18.5% of antibiotic treated group developed AAD, but only 5% of patients treated with antibiotics and LcS. Following antibiotic therapy, a decrease in the abundance of total Bacteria, Clostridium cluster IV and XI, Bifidobacterium spp. and butyryl-CoA CoA transferase genes was observed, whereas Enterobacteriaceae increased. LcS intervention reduced the antibiotic-associated decrease in the diversity of microbiota, increased the abundance of Lactobacillus spp. and reduced the antibiotic-induced decrease of Bifidobacterium spp. Conclusions Antibiotic treatment affects the diversity and the composition of the microbiota impairing butyrate production. Intervention with certain Lactobacillus strains may antagonise some of these changes, and more potent short-chain fatty acid-stimulating probiotics are desirable for intervention in AAD.