Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli.

2.50
Hdl Handle:
http://hdl.handle.net/10033/16276
Title:
Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli.
Authors:
Coldewey, Sina M; Hartmann, Maike; Schmidt, Dorothea S; Engelking, Uta; Ukena, Sya N; Gunzer, Florian
Abstract:
BACKGROUND: Enterohemorrhagic E. coli (EHEC), a subgroup of Shiga toxin (Stx) producing E. coli (STEC), may cause severe enteritis and hemolytic uremic syndrome (HUS) and is transmitted orally via contaminated foods or from person to person. The infectious dose is known to be very low, which requires most of the bacteria to survive the gastric acid barrier. Acid resistance therefore is an important mechanism of EHEC virulence. It should also be a relevant characteristic of E. coli strains used for therapeutic purposes such as the probiotic E. coli Nissle 1917 (EcN). In E. coli and related enteric bacteria it has been extensively demonstrated, that the alternative sigma factor sigmaS, encoded by the rpoS gene, acts as a master regulator mediating resistance to various environmental stress factors. METHODS: Using rpoS deletion mutants of a highly virulent EHEC O26:H11 patient isolate and the sequenced prototype EHEC EDL933 (ATCC 700927) of serotype O157:H7 we investigated the impact of a functional rpoS gene for orchestrating a satisfactory response to acid stress in these strains. We then functionally characterized rpoS of probiotic EcN and five rpoS genes selected from STEC isolates pre-investigated for acid resistance. RESULTS: First, we found out that ATCC isolate 700927 of EHEC EDL933 has a point mutation in rpoS, not present in the published sequence, leading to a premature stop codon. Moreover, to our surprise, one STEC strain as well as EcN was acid sensitive in our test environment, although their cloned rpoS genes could effectively complement acid sensitivity of an rpoS deletion mutant. CONCLUSION: The attenuation of sequenced EHEC EDL933 might be of importance for anyone planning to do either in vitro or in vivo studies with this prototype strain. Furthermore our data supports recently published observations, that individual E. coli isolates are able to significantly modulate their acid resistance phenotype independent of their rpoS genotype.
Affiliation:
Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany. sina.coldewey@web.de <sina.coldewey@web.de>
Citation:
Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli. 2007, 7:21 BMC Microbiol.
Journal:
BMC microbiology
Issue Date:
2007
URI:
http://hdl.handle.net/10033/16276
DOI:
10.1186/1471-2180-7-21
PubMed ID:
17386106
Type:
Article
Language:
en
ISSN:
1471-2180
Appears in Collections:
Publications of RG Mucosal Immunity (MI)

Full metadata record

DC FieldValue Language
dc.contributor.authorColdewey, Sina M-
dc.contributor.authorHartmann, Maike-
dc.contributor.authorSchmidt, Dorothea S-
dc.contributor.authorEngelking, Uta-
dc.contributor.authorUkena, Sya N-
dc.contributor.authorGunzer, Florian-
dc.date.accessioned2008-01-17T14:24:19Z-
dc.date.available2008-01-17T14:24:19Z-
dc.date.issued2007-
dc.identifier.citationImpact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli. 2007, 7:21 BMC Microbiol.en
dc.identifier.issn1471-2180-
dc.identifier.pmid17386106-
dc.identifier.doi10.1186/1471-2180-7-21-
dc.identifier.urihttp://hdl.handle.net/10033/16276-
dc.description.abstractBACKGROUND: Enterohemorrhagic E. coli (EHEC), a subgroup of Shiga toxin (Stx) producing E. coli (STEC), may cause severe enteritis and hemolytic uremic syndrome (HUS) and is transmitted orally via contaminated foods or from person to person. The infectious dose is known to be very low, which requires most of the bacteria to survive the gastric acid barrier. Acid resistance therefore is an important mechanism of EHEC virulence. It should also be a relevant characteristic of E. coli strains used for therapeutic purposes such as the probiotic E. coli Nissle 1917 (EcN). In E. coli and related enteric bacteria it has been extensively demonstrated, that the alternative sigma factor sigmaS, encoded by the rpoS gene, acts as a master regulator mediating resistance to various environmental stress factors. METHODS: Using rpoS deletion mutants of a highly virulent EHEC O26:H11 patient isolate and the sequenced prototype EHEC EDL933 (ATCC 700927) of serotype O157:H7 we investigated the impact of a functional rpoS gene for orchestrating a satisfactory response to acid stress in these strains. We then functionally characterized rpoS of probiotic EcN and five rpoS genes selected from STEC isolates pre-investigated for acid resistance. RESULTS: First, we found out that ATCC isolate 700927 of EHEC EDL933 has a point mutation in rpoS, not present in the published sequence, leading to a premature stop codon. Moreover, to our surprise, one STEC strain as well as EcN was acid sensitive in our test environment, although their cloned rpoS genes could effectively complement acid sensitivity of an rpoS deletion mutant. CONCLUSION: The attenuation of sequenced EHEC EDL933 might be of importance for anyone planning to do either in vitro or in vivo studies with this prototype strain. Furthermore our data supports recently published observations, that individual E. coli isolates are able to significantly modulate their acid resistance phenotype independent of their rpoS genotype.en
dc.language.isoenen
dc.subject.meshAcidsen
dc.subject.meshBase Sequenceen
dc.subject.meshDrug Resistance, Bacterialen
dc.subject.meshEscherichia colien
dc.subject.meshEscherichia coli O157en
dc.subject.meshEscherichia coli Proteinsen
dc.subject.meshGene Expression Regulation, Bacterialen
dc.subject.meshGenetic Complementation Testen
dc.subject.meshGenotypeen
dc.subject.meshHydrogen-Ion Concentrationen
dc.subject.meshMolecular Sequence Dataen
dc.subject.meshPoint Mutationen
dc.subject.meshProbioticsen
dc.subject.meshSequence Alignmenten
dc.subject.meshSigma Factoren
dc.titleImpact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli.en
dc.typeArticleen
dc.contributor.departmentInstitute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany. sina.coldewey@web.de <sina.coldewey@web.de>en
dc.identifier.journalBMC microbiologyen

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