Factors involved in the interaction between Bifidobacterium and the host mucosal surface

The human gut microbiome includes commensal bacteria from genus Bifidobacterium, which primarily colonizes the region from the small intestine to the colon. This region has a mucus layer composed mainly of mucin glycoproteins. In addition to providing a habitat for the microbiota, the mucus is also a potential glycan source. Therefore, interaction with mucus could provide a competitive advantage for Bifidobacterium within the gut ecosystem. In this review, we first outline the role of Bifidobacterium extracellular proteins in bacterium-mucus interactions, and then we focus on extracellular glycoside hydrolases and a recently discovered pilus-mediated colonization process unique