Lessons from the genomes of bifidobacteria

Abstract

The gut microbiota is a complex ecosystem composed of hundreds of different bacterial species that altogether play an important role in the physiology of their host. In the past few years the complete genome sequence of a number of bacterial strains isolated from the human gastrointestinal tract has been established including that of Bifidobacterium longum NCC2705 isolated from the feces of a healthy infant. Bifidobacteria are among the first species to colonise the human gastrointestinal tract and as such are believed to play an important role in gut homeostasis and normal development. The genome sequence of NCC2705 has revealed a number of features that suggest how this bacterium has adapted to its environment and that could help understanding how it interacts with its host. Here, we review general features of bifidobacteria and illustrate how genome-based approaches can help us better understand the biology of these organisms.

Characterization of the complex bacterial communities colonizing biliary stents reveals a host-dependent diversity

“…Although the global differences between stent communities from different hospitals were only minor, the slight divergence between the BS and SZ samples was because of the higher prevalence of Bifidobacteria in biofilms from SZ stents. Bifidobacteria are autochthonous bacteria in the gastrointestinal tract (Klijn et al, 2005), but so far they have not been characterized as abundant in biliary stents. Culture-independent studies on the small intestine found them to be in low abundance (Hayashi et al, 2005;Wang et al, 2005), whereas they are more abundant in the colon and have been reported to comprise 3.3% in faeces (Vaughan et al, 2002).…”

Carbohydrate metabolism in Bifidobacteria

“…Metagenomic analyses allowed estimates of the total number of bacterial species that may be contained within the intestinal microbiota, ranging from approximately 500 to 1,000 distinct bacterial species [25,34], to between 15,000 and 36,000 different species [29]. A very recent study on the minimal human gut metagenome has estimated that an individual harbours at least 160 prevalent bacterial species [99], which are also found in other individuals and which together form a complex community that colonizes the oral cavity, stomach, and small and large intestines in varying numbers [22,58,82]. The total number of bacterial cells is at least 10 times more than the sum of all human cells in a body [39], while the collective genome of all these bacterial cells, also termed the microbiome, consists of at least 150 times more genes than the total number of genes present in the human genome [99].…”

Safety ofBifidobacterium animalissubsp.lactis(B. lactis) strain BB-12-supplemented yogurt in healthy adults on antibiotics: a phase I safety study

“…Bifidobacterium species, particularly Bifidobacterium animalis subsp lactis (B. lactis), strain BB-12 (BB-12), the principal focus of this study, can be found in the gastrointestinal tract as both autochthonous (indigenous) and allochthonous (derived from outside a system) residents. 9 Newborns, especially those that are breast-fed, are colonized with bifidobacteria within days after birth. Once the infant is weaned, the population of this genus in the colon appears to be relatively stable until advanced age when it appears to decline.…”

“…Once the infant is weaned, the population of this genus in the colon appears to be relatively stable until advanced age when it appears to decline. 9,10 This research was done to determine the safety of strawberryflavored yogurt supplemented with the strain BB-12 and to determine the effect of probiotic treatment on whole blood cell expression of inflammatory response-associated genes. This trial serves as the first in a two-stage process to establish the safety profile of a BB-12-supplemented yogurt drink in adults and children.…”