Microscopic localization analysis revealed exclusive utilization of human intestinal starch granules by Bifidobacterium adolescentis

Abstract

It is expected that various diseases can be treated or prevented by controlling the intestinal microbiota, however, there are large individual differences in the response to microbiota-targeted interventions. This could be attributed to individual differences in the commensal bacterial community and competition among bacteria for nutrients. In this review, we discuss the significance of microscopic localization analysis of bacteria in elucidating the process by which individual bacteria acquire nutrients in a competitive environment. We used human stool sections to explore the localization of bacteria around food residues and found that Bifidobacterium adolescentis colonizes on starch granules in the intestine. This colonization was observed in every carrier of the species during ingestion of starch granules, and the species increased significantly and preferentially over other species upon the ingestion. The main bacterial species and the main organic acid that increased upon the ingestion differed by the presence or absence of the species, and the consumption efficiency of the starch granules in the intestine differed as well. These results indicate that bacterial colonization can contribute to the exclusive and efficient utilization of solid nutrients in the human gut, and that the effect of a nutrient on the gut and human body can vary depending on the presence or absence of the main colonizing bacterial species.