Survival of microorganisms from modern probiotics in model conditions of the intestine

Abstract

Introduction. The staye of intestinal microflora affects the work of the whole organism. When composition of normal ibtestine microflora changes, its restoration is required. In our days a wide variety of probiotic drugs are available on the market which can be used to solve this problem. Most bacteria having probiotic properties represent the families Lactobacillus and Bifidobacterium, which have poor resistance to acidic content of the stomach and toxic effects of bile salts. Various studies have clearly shown that in a person with normal acidic and bile secretion, the lactobacilli and bifidobacteria are not detected after the passage through the duodenum, i.e., they perish before reaching the small intestines. In this study we compared the survival of different microorganisms which are contained in 9 probiotic drugs in a model of gastric and intestinal environments.Material and methods. In the laboratory of SI: “Mechnikov Institute Microbiology and Immunology, National Ukrainian Academy Medical Sciences" the in vitro experimentshave been evaluated to test the ability of different probiotic bacteria which were contained in 9 probiotic drugs to survive the impact of the model environment of the stomach and duodenum. Bacillus coagulans persistence was evaluated under impact of simulated environment of the stomach and duodenum, it also was assessed by the quantity of CFU by incubation on culture medium. The following were studied: Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus reuteri, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus bulgaricus, Bifidobacterium bifidum, Bifidobacterium longum , Bifidobacterium breve, Bifidobacterium infantis, Bifidobacterium animalis subsp. Lactis BB-12, Saccharomyces boulardii, Bacillus coagulans, Bacillus clausii, Enterococcus faecium. Microorganisms were incubated for 3 hours in a model environment of the stomach (pepsin 3 g / l, hydrochloric acid of 160 mmol / l, pH 2.3), later after centrifugation and washing, they were incubated for 3 hours in intestinal model environment (bile salts 3% pancreatin 0.1%, pH 7.0). Inoculation was performed before incubation, after incubation in the gastric medium and after incubation in intestinal medium. We used the medium corresponding to the studied genus of bacteria - MRS-environment for lactobacilli, bifidum for Bifidobacterium, sabouraud medium for the isolation of yeasts and fungi and endo agar for the isolation of Enterobacteriaceae. We assessed the quantity of CFU before and after impact.Results and discussion. After incubation in a simulated gastric environment, bacteria of the type  Lactobacillus and Bifidobacterium did not survive and were not defined. Only Bacillus coagulans and Saccharomyces boulardii were resistant. These microorganisms grew after incubation in the same amount as before incubation - 10^5-6 and 10^7-8 CFU respectively. Bacillus clausii also survived in these conditions, but to a lesser extent: initially - 10⁷ CFU, after incubation - 10⁵ CFU. After staying in model environment of the duodenum Bacillus coagulans and Saccharomyces boulardii were still fully viable, and the number of germinating Bacillusclausii bacteria decreased by an order - up to 10⁴ CFU.Conclusion. The probiotics containing Bacillus coagulans and Saccharomyces boulardii showed complete resistance to the impact of the model environment of the stomach and duodenum, Bacillus clausii was partially resistant. It leads to conclusion that probiotic drugs containing lactobacilli and bifidobacteria, cannot withstand the aggressive environmental influence of the stomach and duodenum and become inactivated under their influence. Probiotic drugs Enterol containing yeast Saccharomyces boulardii, and Laktovit Forte containing the spore-forming bacterium Bacillus coagulans are completely resistant to the action of the model environment of the stomach and duodenum.