The composition, influencing factors, and physiological functions of bifidobacteria in the infant gut: a review.

Bifidobacteria are naturally found in the human gut and quickly establish dominance shortly after birth, playing a crucial role in the development and stability of the infant gut microbiota. A growing body of research suggests that host and environmental factors shape the colonization and the relative abundance of bifidobacteria in the infant gut during early life. Understanding the factors that influence bifidobacterial colonization and maintaining normal colonization levels are keys to ensuring gut health. Bifidobacteria exhibit antibacterial, anti-inflammatory, and pathogen-resistant properties, and have the ability to maintain intestinal microbiota homeostasis. Clinically, they have been widely used to manage manifestations of various conditions, such as constipation, diarrhea, inflammatory bowel disease, and liver injury. This review focuses on the composition of bifidobacteria in the infant gut, the relevant factors influencing their colonization and abundance, and their physiological functions, to advance a deeper comprehension of the health-protective role and mechanisms of bifidobacteria within the host microbiome. This information provides an important basis for further understanding the underlying mechanisms of action, and lays the foundation for developing Bifidobacterium-based interventions to promote the healthy development of the infant gut microbiome and prevent related diseases.