Bifidobacterium Species Colonization in Infancy: A Global Cross-Sectional Comparison by Population History of BreastFeeding

Bifidobacterium are a beneficial and dominant member of the breast-fed infant gut microbiome. However, the health benefits of Bifidobacterium are partially species dependent. Here we characterize the species and subspecies of Bifidobacterium present in breastfed infants around the world. Across populations, three distinct patterns of Bifidobacterium colonization emerged: 1) Dominance of Bifidobacterium longum subspecies infantis, 2) Prevalent Bifidobacterium of multiple species, and 3) Frequent absence of Bifidobacterium. These patterns appear related to country history of breastfeeding, with infants in countries with historically high rates of long duration breastfeeding more likely to be colonized by B. longum subspecies infantis compared with infants in countries with histories of shorter duration breastfeeding. These findings highlight the need to consider historical and cultural influences on gut commensal survival influence present day colonization patterns in order to understand epidemiological transmission patterns of Bifidobacterium and other major gut commensals.