Abstract
Bifidobacterium longum subsp. infantis (B. infantis) is one of a few microorganisms capable of metabolizing human breast milk and is a pioneer colonizer in the guts of breastfed infants. One current challenge is differentiating B. infantis from its close relatives, B. longum and B. suis. All three organisms are classified in the same species group but only B. infantis can metabolize human milk oligosaccharides (HMOs). We compared HMO-metabolizing genes across different Bifidobacterium genomes and developed B. infantis-specific primers to determine if the genes alone or the primers can be used to quickly characterize B. infantis. We showed that B. infantis is uniquely identified by the presence of five HMO-metabolizing gene clusters, tested for its prevalence in infant gut metagenomes, and validated the results using the B. infantis-specific primers. We observed that only 15 of 203 (7.4%) children under 2 years old from a cohort of US children harbored B. infantis. These results highlight the importance of developing and improving approaches to identify B. infantis. A more accurate characterization may provide insights into regional differences of B. infantis prevalence in infant gut microbiota.
Highlights
Human microbiota has coevolved with humans for tens of thousands of years [1]
Genomes included 4 Bifidobacterium breve and 383 strains belonging to Bifidobacterium longum group, spanning all three subspecies (43 B. infantis, 167 B. longum, 3 B. suis)
average nucleotide identity (ANI) is an in silico substitute for DNA-DNA hybridization (DDH) and is useful for delineating species boundaries [22]
Summary
Human microbiota has coevolved with humans for tens of thousands of years [1]. This coexistence requires a tight partnership between the host and its resident microorganisms.For example, the abundant oligosaccharides found in human milk cannot be digested by the infant who feeds on them. Human microbiota has coevolved with humans for tens of thousands of years [1]. This coexistence requires a tight partnership between the host and its resident microorganisms. The abundant oligosaccharides found in human milk cannot be digested by the infant who feeds on them. Instead, these are used to support the growth of the pioneer gut colonizers, who in turn, support the development of the infant [2,3]. Taxa in the Bifidobacterium genus often have genes that allow them to metabolize the complex carbohydrates in their hosts [4,5,6].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
