title: Assessment of metabolic diversity within the intestinal microbiota from healthy humans using combined molecular and cultural approaches.
abstract: The human gut harbours a wide range of bacterial communities that play key roles in supplying nutrients and energy to the host through anaerobic fermentation of dietary components and host secretions. This fermentative process involves different functional groups of microorganisms linked in a trophic chain. Although the diversity of the intestinal microbiota has been studied extensively using molecular techniques, the functional aspects of this biodiversity remain mostly unexplored. The aim of the present work was to enumerate the principal metabolic groups of microorganisms involved in the fermentative process in the gut of healthy humans. These functional groups of microorganisms were quantified by a cultural approach, while the taxonomic composition of the microbiota was assessed by in situ hybridization on the same faecal samples. The functional groups of microorganisms that predominated in the gut were the polysaccharide-degrading populations involved in the breakdown of the most readily available exogenous and endogenous substrates and the predominant butyrate-producing species. Most of the functional groups of microorganisms studied appeared to be present at rather similar levels in all healthy volunteers, suggesting that optimal numbers of these various bacterial groups are crucial for efficient gut fermentation, as well as for host nutrition and health. Significant interindividual differences were, however, confirmed with respect to the numbers of methanogenic archaea, filter paper-degrading and acetogenic bacteria and the products formed by lactate-utilizing bacteria.
authors.affiliation: INRA, Unité de Microbiologie UR 454, Centre de Recherches de Clermont-Ferrand-Theix, Saint Genès-Champanelle, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Chassard
authors.forename: Karen P
authors.initials: KP
authors.lastname: Scott
authors.forename: Perrine
authors.initials: P
authors.lastname: Marquet
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Martin
authors.forename: Christophe
authors.initials: C
authors.lastname: Del'homme
authors.forename: Michel
authors.initials: M
authors.lastname: Dapoigny
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Flint
authors.forename: Annick
authors.initials: A
authors.lastname: Bernalier-Donadille
mesh_terms: D000328:Adult; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D044822:Biodiversity; D015169:Colony Count, Microbial; D004043:Dietary Fiber / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D017404:In Situ Hybridization, Fluorescence; D007422:Intestines / Q000382:microbiology*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008697:Methane / Q000378:metabolism; D008875:Middle Aged; D055815:Young Adult
chemical_list: D004043:Dietary Fiber; D005227:Fatty Acids; D019344:Lactic Acid; D006859:Hydrogen; D008697:Methane