Adaptation of bifidobacteria to the gastrointestinal tract and functional consequences.

Members of the genus Bifidobacterium are considered to be important constituents of the microbiota of animals, from insects to mammals. They are gut commensals extensively used by the food industry as probiotic microorganisms, since some strains have been shown to have specific beneficial effects. However, the molecular processes underlying their functional capacities to promote a healthy status in the host, as well as those involved in survival, colonization and persistence of bifidobacteria in the gut, are far from being completely understood. This review summarizes the current knowledge on the mechanisms used by bifidobacteria to cope with gastrointestinal factors and to adapt to them, and discusses the advantages of the adaptive traits acquired by these microorganisms as a consequence of their interactions with the gastrointestinal tract environment, as well as the impact of such adaptations in the functional characteristics of bifidobacteria.