Impact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli.
Cast your vote
You can rate an item by clicking the amount of stars they wish to award to this item.
When enough users have cast their vote on this item, the average rating will also be shown.
Your vote was cast
Thank you for your feedback
Thank you for your feedback
MetadataShow full item record
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.
CitationImpact of the rpoS genotype for acid resistance patterns of pathogenic and probiotic Escherichia coli. 2007, 7:21 BMC Microbiol.
AffiliationInstitute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany. firstname.lastname@example.org <email@example.com>
- Antagonistic effects of probiotic Escherichia coli Nissle 1917 on EHEC strains of serotype O104:H4 and O157:H7.
- Authors: Rund SA, Rohde H, Sonnenborn U, Oelschlaeger TA
- Issue date: 2013 Jan
- [Construction and immunization of a enterohemorrhagic Escherichia coli O157 attenuated].
- Authors: Liu J, Sun Y, Feng SZ
- Issue date: 2007 Mar
- Comparative analysis of transcriptional regulatory elements of glutamate-dependent acid-resistance systems of Shigella flexneri and Escherichia coli O157:H7.
- Authors: Bhagwat AA, Bhagwat M
- Issue date: 2004 May 1
- Global effect of RpoS on gene expression in pathogenic Escherichia coli O157:H7 strain EDL933.
- Authors: Dong T, Schellhorn HE
- Issue date: 2009 Aug 3
- Functional heterogeneity of RpoS in stress tolerance of enterohemorrhagic Escherichia coli strains.
- Authors: Bhagwat AA, Tan J, Sharma M, Kothary M, Low S, Tall BD, Bhagwat M
- Issue date: 2006 Jul