Cross-feeding by Bifidobacterium breve UCC2003 during co-cultivation with Bifidobacterium bifidum PRL2010 in a mucin-based medium.

Muireann Egan,Lokesh Joshi,Douwe Van Sinderen,Mary O’Connell Motherway,Michelle Kilcoyne,Marian Kane,Marco Ventura

doi:10.1186/s12866-014-0282-7

Abstract

BackgroundBifidobacteria constitute a specific group of commensal bacteria that commonly inhabit the mammalian gastrointestinal tract. Bifidobacterium breve UCC2003 was previously shown to utilize a variety of plant/diet/host-derived carbohydrates, including cellodextrin, starch and galactan, as well as the mucin and HMO-derived monosaccharide, sialic acid. In the current study, we investigated the ability of this strain to utilize parts of a host-derived source of carbohydrate, namely the mucin glycoprotein, when grown in co-culture with the mucin-degrading Bifidobacterium bifidum PRL2010.ResultsB. breve UCC2003 was shown to exhibit growth properties in a mucin-based medium, but only when grown in the presence of B. bifidum PRL2010, which is known to metabolize mucin. A combination of HPAEC-PAD and transcriptome analyses identified some of the possible monosaccharides and oligosaccharides which support this enhanced co-cultivation growth/viability phenotype.ConclusionThis study describes the potential existence of a gut commensal relationship between two bifidobacterial species. We demonstrate the in vitro ability of B. breve UCC2003 to cross-feed on sugars released by the mucin-degrading activity of B. bifidum PRL2010, thus advancing our knowledge on the metabolic adaptability which allows the former strain to colonize the (infant) gut by its extensive metabolic abilities to (co-)utilize available carbohydrate sources.

Highlights

Bifidobacteria constitute a specific group of commensal bacteria that commonly inhabit the mammalian gastrointestinal tract
We recently demonstrated that B. breve UCC2003 can cross-feed on sialic acid derived from the metabolism of 3′ sialyllactose, an abundant human milk oligosaccharide (HMO), by B. bifidum PRL2010 [13]
Growth of B. breve UCC2003 on mucin Growth of B. breve UCC2003-pAM5 and B. bifidum PRL2010-pPKCM7 in modified deMan Rogosa Sharpe (mMRS) supplemented with 0.4% mucin, independently or in co-culture, was measured by viable plate counts over 72 h

Summary

Introduction

Bifidobacteria constitute a specific group of commensal bacteria that commonly inhabit the mammalian gastrointestinal tract. Bifidobacterium breve UCC2003 was previously shown to utilize a variety of plant/diet/host-derived carbohydrates, including cellodextrin, starch and galactan, as well as the mucin and HMO-derived monosaccharide, sialic acid. Bifidobacteria have attracted attention due to the purported health benefits associated with their presence in the gut Such beneficial contributions include development and modulation of the immune system [2], provision of vitamins [3], and protection against pathogenic bacteria [4]. B. breve UCC2003 was shown to utilize the mucin- and human milk oligosaccharide (HMO)-derived monosaccharide sialic acid [13], which is more consistent with this strain’s origin as a nursling stool isolate from a breast-fed infant, where it would be expected to metabolize HMOs and/or the structurally similar oligosaccharides found in mucin glycoproteins. Host-derived oligosaccharides are believed to form part of the nutrient resource for certain intestinal bacteria

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