Living cells of probiotic Bifidobacterium bifidum YIT 10347 detected on gastric mucosa in humans

<jats:p>The probiotic strain <jats:italic>Bifidobacterium bifidum</jats:italic> YIT 10347 has been demonstrated to inhibit <jats:italic>Helicobacter pylori</jats:italic> activity, prevent injury to the gastric mucosa, and improve general gastric malaise symptoms in <jats:italic>H. pylori</jats:italic> positive patients. This study aimed to investigate the adhering activity and localisation of <jats:italic>B. bifidum</jats:italic> YIT 10347 to gastric cells and tissue <jats:italic>in vitro</jats:italic>, and in human <jats:italic>in vivo</jats:italic> to clarify the mechanism of its beneficial effects on the stomach. The <jats:italic>in vitro</jats:italic> study found the adhesion rate of <jats:italic>B. bifidum</jats:italic> YIT 10347 to human gastric epithelial cells was about 10 times higher than that of lactic acid bacteria and other bifidobacteria. In the human study, 5 <jats:italic>H. pylori</jats:italic> negative and 12 <jats:italic>H. pylori</jats:italic> positive subjects ingested milk fermented with <jats:italic>B. bifidum</jats:italic> YIT 10347. <jats:italic>B. bifidum</jats:italic> YIT 10347 cells were measured by RT-qPCR for in gastric biopsy samples. Living <jats:italic>B. bifidum</jats:italic> YIT 10347 cells were detected in the biopsy samples in <jats:italic>H. pylori</jats:italic> negative subjects (105 cells/g and 104 cells/g at 1 h and 2 h after ingestion, respectively) and <jats:italic>H. pylori</jats:italic> positive subjects (104 cells/g at 1 h after the ingestion). Moreover, immunostaining analysis of tissue sections found that <jats:italic>B. bifidum</jats:italic> YIT 10347 cells were located at the interstitial mucin layer of the stomach. These results suggest that cells of probiotic <jats:italic>B. bifidum</jats:italic> YIT 10347 adhered to the human gastric mucosa in a live state, and that the higher adhering activity of <jats:italic>B. bifidum</jats:italic> YIT 10347 to the gastric mucosa may be involved in its beneficial effects on the human stomach.</jats:p>