Differential effects of short-chain fatty acids and iron on expression of iha in Shiga-toxigenic Escherichia coli

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dc.contributor.authorHerold, S.
dc.contributor.authorPaton, J.
dc.contributor.authorSrimanote, P.
dc.contributor.authorPaton, A.
dc.date.issued2009
dc.description.abstractShiga-toxigenic Escherichia coli (STEC) colonizing the bowel are exposed to a variety of short-chain fatty acids (SCFAs), including acetate, propionate and butyrate, produced by gut microflora. However, the total concentrations and relative amounts of SCFAs in the lumen vary with intestinal niche. Here we report that conditions simulating SCFA concentrations present in the human gut trigger expression of the iha gene, which encodes an adherence-conferring outer-membrane protein of pathogenic E. coli. We show that growth under conditions simulating colonic, but not ileal, SCFA concentrations increases iha expression in three tested STEC strains, with the strongest expression detected in LEE-negative STEC O113:H21 strain 98NK2. Expression of iha is known to be subject to Fur-mediated iron repression in O157:H7 STEC, and the same occurs in 98NK2. However, exogenous iron did not repress iha expression in the presence of colonic SCFAs in either 98NK2 or the O157:H7 strain EDL933. Moreover, exposure to the iron chelator 2,2'-dipyridyl caused no further enhancement of iha expression over that induced by colonic SCFAs. These findings indicate that SCFAs regulate iha expression in STEC independently of iron. Increased expression of iha under colonic but not ileal SCFA conditions possibly may contribute to preferential colonization of the human colon by STEC.
dc.description.statementofresponsibilitySylvia Herold, James C. Paton, Potjanee Srimanote and Adrienne W. Paton
dc.identifier.citationMicrobiology, 2009; 155(11):3554-3563
dc.identifier.doi10.1099/mic.0.029454-0
dc.identifier.issn1350-0872
dc.identifier.issn1465-2080
dc.identifier.orcidPaton, J. [0000-0001-9807-5278]
dc.identifier.urihttp://hdl.handle.net/2440/57214
dc.language.isoen
dc.publisherSoc General Microbiology
dc.relation.granthttp://purl.org/au-research/grants/nhmrc/284214
dc.relation.granthttp://purl.org/au-research/grants/nhmrc/565359
dc.source.urihttps://doi.org/10.1099/mic.0.029454-0
dc.subjectColon
dc.subjectIleum
dc.subjectIron
dc.subjectFatty Acids, Volatile
dc.subjectBacterial Outer Membrane Proteins
dc.subjectEscherichia coli Proteins
dc.subjectDNA, Bacterial
dc.subjectCulture Media
dc.subjectBacterial Adhesion
dc.subjectGene Expression Regulation, Bacterial
dc.subjectMutagenesis
dc.subjectShiga-Toxigenic Escherichia coli
dc.titleDifferential effects of short-chain fatty acids and iron on expression of iha in Shiga-toxigenic Escherichia coli
dc.typeJournal article
pubs.publication-statusPublished

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