摘要：SummaryDiet-microbe interactions play a crucial role in modulation of the early life microbiota and infant health.Bifidobacteriumdominates the breast-fed infant gut and may persist in individuals during transition from a milk-based to a more diversified diet. Here, we investigated adaptation ofBifidobacterium longumto the changing nutritional environment. Genomic characterization of 75 strains isolated from nine either exclusively breast- or formula-fed (pre-weaning) infants in their first 18 months revealed subspecies- and strain-specific intra-individual genomic diversity with respect to carbohydrate metabolism, which corresponded to different dietary stages. Complementary phenotypic studies indicated strain-specific differences in utilization of human milk oligosaccharides and plant carbohydrates, whereas proteomic profiling identified gene clusters involved in metabolism of selected carbohydrates. Our results indicate a strong link between infant diet andB.longumdiversity and provide additional insights into possible competitive advantage mechanisms of thisBifidobacteriumspecies and its persistence in a single host.Graphical AbstractDisplay OmittedHighlights•B. longumstrains can persist in individual infants despite dietary changes•New strains with additional metabolism capabilities can also be acquired•B. longumcarbohydrate metabolism repertoires are individual and strain-specific•Strains at different dietary stages show genomic adaptations to specific substratesDietary Supplement; Microbiology; Microbiome
