Bifidobacterium bifidum and the infant gut microbiota: an intriguing case of microbe‐host co‐evolution

Abstract

Summary Bifidobacterium bifidum is reported to be among the first colonizers of the newborn's gastrointestinal tract due to its ability to metabolize human milk oligosaccharides (HMOs). In order to investigate biological features that allow this bifidobacterial species to colonize a newborn, bifidobacterial internally transcribed spacer profiling of stool samples of 50 mother‐infant dyads, as well as corresponding breastmilk samples, was performed. Hierarchical clustering based on bifidobacterial population profiles found in infant faecal samples revealed the presence of four bifidobacterial clusters or the so‐called bifidotypes. Bifidobacterium bifidum was shown to be a key member among bifidotypes, in which its presence correlate with several different bifidobacterial species retrieved in infant faecal samples. For this reason, we investigated cross‐feeding behaviour facilitated by B. bifidum on a bioreactor model using human milk as growth substrate. Transcriptional profiles of this strain were evaluated when grown on nine specific glycans typically constituting HMOs. Remarkably, these analyses suggest extensive co‐evolution with the host and other bifidobacterial species in terms of resource provision and sharing, respectively, activities that appear to support a bifidobacteria‐dominant microbiome.

The infant gut microbiome as a microbial organ influencing host well-being

“…Amongst the 80 (sub) species bifidobacteria so far recognized by the International Commission of Bacterial Taxonomy [122], it is possible to identify bifidobacterial species which elicit a rather broad host species preference, i.e., engaging in a cosmopolitan lifestyle [122]. Intriguingly, Bifidobacterium bifidum, Bifidobacterium breve and Bifidobacterium longum are specifically identified in the human gut and have been shown to represent part of the dominant bacterial members of the gut microbiota of breast-fed infants [120,123].…”

“…Chemically similar host-glycans are represented by HMOs, which are consequently efficiently degraded by many members of the B. bifidum species, including PRL2010 [123,146].…”

Bifidobacterial Distribution Across Italian Cheeses Produced from Raw Milk

“…Members of the genus Bifidobacterium have been shown to represent common gut colonizers of many occupants on the mammalian branch of the tree of life [12]. During the last two decades bifidobacteria have been extensively studied for their contribution to elicit a range of host health benefits, specifically during the first stages of life [13][14][15]. Among such reported health-promoting activities, bifidobacteria have been associated with key physiological aspects in infants, for example, the induction of mucus layer production and development of the gastro-intestinal tract, along with protection against (opportunistic) pathogens and maturation of the immune system [16][17][18].…”

Structural features, interaction with the gut microbiota and anti-tumor activity of oligosaccharides

“…Functional oligosaccharides can affect the abundance and composition of gut microbiota, so that they can selectively proliferate probiotics and produce metabolites with biological activity such as SCFAs. 66 Functional oligosaccharides can promote the production and absorption of certain essential micronutrients and short chain fatty acids (SCFAs; primarily butyric acid, propionic acid, and butyric acid), 67 with the latter possibly exerting benecial effects such as appetite and glycemic control, anti-inammation, immune regulation, and antitumor activity. With a few references related to XOS, how XOS combat tumor with the help of gut microbiota can be comprehensively described.…”

“…A large number of researches on the gut microbiome's role in infection and inammation control have initially revealed how specic microbiota and their metabolites affect the natural immune system. 66 SCFAs are mainly bacterial metabolites, playing wide roles in immunity. 95,96 SCFAs enter cells through passive diffusion, vector-mediated transport, and interaction with GPCRs (g-protein-coupled receptors) in colon.…”