Molecular detection of Bifidobacterium animalis DN-173010 in human feces during fermented milk administration

Abstract

We tested different techniques to detect exogenous bifidobacteria (DN-173010) in feces; genus- and species-specific PCR technique; amplified ribosomal DNA restriction analysis (ARDRA) and fluorescent in situ hybridization (FISH) technique. A significant increase in the number of bifidobacteria in feces was observed during ingestion of fermented milk, and also, we detected a decrease in this number when the ingestion stopped. The number of bifidobacteria enumerated by culturing was 10–100-fold lower than by FISH technique. Bifidobacterium animalis DN-173010 can survive passage through the gastrointestinal tract and was detected viable in human feces. Combination of ARDRA and FISH was a powerful tool to detect exogenous bifidobacteria. The aim of this study is to demonstrate that Bifidobacterium DN-173010 can survive passage through the gastrointestinal tract and be recovered live in human feces. For this purpose, we have assessed different techniques to detect and quantify the number of bifidobacteria following fermented milk supplemented with B. animalis subsp. lactis DN-173010 administration and to confirm that this strain can survive passage through the gastrointestinal tract by recovering viable cells in human feces.