Document Detail

Composition and metabolic activities of bacterial biofilms colonizing food residues in the human gut.
MedLine Citation:
PMID:  16957247     Owner:  NLM     Status:  MEDLINE    
Bacteria growing in the human large intestine live in intimate association with the host and play an important role in host digestive processes, gut physiology, and metabolism. Fecal bacteria have been investigated extensively, but few studies have been done on biofilms that form on digestive wastes in the large bowel. The aims of this investigation were to investigate the composition and metabolic activities of bacterial communities that colonize the surfaces of food residues in fecal material, with respect to their role in the fermentation of complex carbohydrates. Fresh stools were obtained from 15 healthy donors, and food residues were separated by filtration. Adherent bacteria were removed by surfactant treatment for microbiological analysis and fermentation studies. Scanning electron microscopy and fluorescent in situ hybridization in conjunction with confocal laser scanning microscopy (CLSM) were used to visualize intact biofilms. Results showed that bacterial populations strongly adhering to particulate matter were phenotypically similar in composition to unattached communities, with bacteroides and bifidobacteria predominating. Biofilms comprised a mixture of living and dead bacteria, and CLSM showed that bifidobacteria in the biofilms occurred as isolated dispersed cells and in microcolonies near the interface with the substratum. Fermentation experiments with a variety of complex carbohydrates demonstrated that biofilm populations were more efficient in digesting polysaccharides, while nonadhering communities fermented oligosaccharides most rapidly. Acetate was the principal fermentation product formed by biofilm bacteria, whereas higher levels of butyrate were produced by nonadherent populations, showing that the two communities were metabolically distinct.
Sandra Macfarlane; George T Macfarlane
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  72     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  2006 Sep 
Date Detail:
Created Date:  2006-09-07     Completed Date:  2006-11-08     Revised Date:  2013-06-07    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6204-11     Citation Subset:  IM    
Gut Group, University of Dundee, Level 6, Ninewells Hospital Medical School, Dundee DD1 9SY, United Kingdom.
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MeSH Terms
Bacteria / genetics,  isolation & purification,  metabolism*
Base Sequence
Biofilms / growth & development*
Carbohydrate Metabolism
DNA Probes / genetics
DNA, Bacterial / genetics
Digestive System / microbiology*
Feces / microbiology
Food Microbiology*
In Situ Hybridization, Fluorescence
Microscopy, Confocal
Microscopy, Electron, Scanning
Reg. No./Substance:
0/DNA Probes; 0/DNA, Bacterial

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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