| Human microbiota-secreted factors inhibit shiga toxin synthesis by enterohemorrhagic Escherichia coli O157:H7. | |
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MedLine Citation:
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PMID: 19064636 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Escherichia coli O157:H7 is a food-borne pathogen causing hemorrhagic colitis and hemolytic-uremic syndrome, especially in children. The main virulence factor responsible for the more serious disease is the Shiga toxin 2 (Stx2), which is released in the gut after oral ingestion of the organism. Although it is accepted that the amount of Stx2 produced by E. coli O157:H7 in the gut is critical for the development of disease, the eukaryotic or prokaryotic gut factors that modulate Stx2 synthesis are largely unknown. In this study, we examined the influence of prokaryotic molecules released by a complex human microbiota on Stx2 synthesis by E. coli O157:H7. Stx2 synthesis was assessed after growth of E. coli O157:H7 in cecal contents of gnotobiotic rats colonized with human microbiota or in conditioned medium having supported the growth of complex human microbiota. Extracellular prokaryotic molecules produced by the commensal microbiota repress stx(2) mRNA expression and Stx2 production by inhibiting the spontaneous and induced lytic cycle mediated by RecA. These molecules, with a molecular mass of below 3 kDa, are produced in part by Bacteroides thetaiotaomicron, a predominant species of the normal human intestinal microbiota. The microbiota-induced stx(2) repression is independent of the known quorum-sensing pathways described in E. coli O157:H7 involving SdiA, QseA, QseC, or autoinducer 3. Our findings demonstrate for the first time the regulatory activity of a soluble factor produced by the complex human digestive microbiota on a bacterial virulence factor in a physiologically relevant context. |
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Authors:
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Thibaut de Sablet; Christophe Chassard; Annick Bernalier-Donadille; Marjolaine Vareille; Alain P Gobert; Christine Martin |
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Publication Detail:
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Type: Journal Article Date: 2008-12-08 |
Journal Detail:
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Title: Infection and immunity Volume: 77 ISSN: 1098-5522 ISO Abbreviation: Infect. Immun. Publication Date: 2009 Feb |
Date Detail:
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Created Date: 2009-01-19 Completed Date: 2009-02-20 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0246127 Medline TA: Infect Immun Country: United States |
Other Details:
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Languages: eng Pagination: 783-90 Citation Subset: IM |
Affiliation:
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INRA, Institut National de la Recherche Agronomique, UR454 Unité de Microbiologie, Centre de Recherche de Clermont-Ferrand/Theix, 63122 Saint-Genès-Champanelle, France. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adolescent Adult Animals Bacteroides / metabolism* Cecum / microbiology Child Child, Preschool Down-Regulation Escherichia coli O157 / metabolism* Feces / microbiology Female Gastrointestinal Contents / microbiology Gene Expression Regulation, Bacterial / physiology Humans Male Quorum Sensing Rats Rats, Inbred F344 SOS Response (Genetics) Shiga Toxin 2 / antagonists & inhibitors, biosynthesis* Transcription, Genetic Virulence Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Shiga Toxin 2 |
| Comments/Corrections | |
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