Assessment of lactobacillus bulgaricus strain in human intestinal samples by denaturation gradient gel electrophoresis

Abstract

PURPOSE. The purpose of this work was to evaluate the content of Lactobacillus bulgaricus in faecal samples of volunteers after consumption of yoghurt produced with selected L. bulgaricus strain. METHODS. Using Denaturation Gradient Gel Electrophoresis (DGGE) the DNA band corresponding to L. bulgaricus was well separated from the DNA bands of other lactobacilli. RESULTS. Faecal samples of all four volunteers consumed yoghurt contained a major DNA band indicating the presence of L. bulgaricus, unlike the faecal samples from the three volunteers no consumed yoghurt where the specific for L. bulgaricus DNA band was absent. The differences in the intensity of the electrophoretic band of L. bulgaricus are influenced by the individuality of the volunteers and the duration of yoghurt consumption. By help of DGGE it was possible to assay the presence of L. bulgaricus in faecal samples and on the base of the intensity of the specific DNA fragment to evaluate the dynamics of L. bulgaricus content during 10 days consumption of yoghurt. CONCLUSIONS. DGGE proved to be an applicable tool to monitor the presence of L. bulgaricus strains in human intestinal samples.