The effect of probiotic strains on the microbiota of the Simulator of the Human Intestinal Microbial EcoSystem (SHIME)

The aim of the present work was to study five potential probiotic strains ( Lactobacillus plantarum, two strains of L. paracasei subsp. paracasei, L. r hamnosus and Bifidobacterium sp.) comparatively in the Simulator of the Hum an Intestinal Microbial Ecosystem (SHIME) in vitro model, and to evaluate t his model as a tool in the screening and selection of probiotic bacteria. T he impact of the strains on the composition of microbiota and its metabolic activities (production of lactic acid and short-chain fatty acids) was stu died. Changes in composition of the microbiota become apparent as a result of probiotic treatment. A marked, but temporary, increase was noted in the number of lactic acid bacteria and bifidobacteria. The profiles of D(-) and L(+) isomers of lactic acid detected in the SHIME after addition of probio tic strains corresponded well to those that are produced in pure culture co nditions. The numbers of enterobacteriaceae decreased markedly and those of clostridia detectably during the intervention, while the enterococci tende d to increase after the treatment. This pattern was similar in the reactors representing both the small and large intestine in the model. The changes in short-chain fatty acids were small, and no definite trend was observed. (C) 1998 Elsevier Science B.V. All rights reserved.