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Type: Journal article
Title: Characterization of Saa, a novel autoagglutinating adhesin produced by locus of enterocyte effacement-negative shiga-toxigenic Escherichia coli strains that are virulent for humans
Author: Paton, A.
Srimanote, P.
Woodrow, M.
Paton, J.
Citation: Infection and Immunity, 2001; 69(11):6999-7009
Publisher: Amer Soc Microbiology
Issue Date: 2001
ISSN: 0019-9567
Statement of
Adrienne W. Paton, Potjanee Srimanote, Matthew C. Woodrow and James C. Paton
Abstract: The capacity of Shiga toxigenic Escherichia coli (STEC) to adhere to the intestinal mucosa undoubtedly contributes to pathogenesis of human disease. The majority of STEC strains isolated from severe cases produce attaching and effacing lesions on the intestinal mucosa, a property mediated by the locus of enterocyte effacement (LEE) pathogenicity island. This element is not essential for pathogenesis, as some cases of severe disease, including hemolytic uremic syndrome (HUS), are caused by LEE-negative STEC strains, but the mechanism whereby these adhere to the intestinal mucosa is not understood. We have isolated a gene from the megaplasmid of a LEE-negative O113:H21 STEC strain (98NK2) responsible for an outbreak of HUS, which encodes an auto-agglutinating adhesin designated Saa (STEC autoagglutinating adhesin). Introduction of saa cloned in pBC results in a 9.7-fold increase in adherence of E. coli JM109 to HEp-2 cells and a semilocalized adherence pattern. Mutagenesis of saa in 98NK2, or curing the wild-type strain of its megaplasmid, resulted in a significant reduction in adherence. Homologues of saa were found in several unrelated LEE-negative STEC serotypes, including O48:H21 (strain 94CR) and O91:H21 (strain B2F1), which were also isolated from patients with HUS. Saa exhibits a low degree of similarity (25% amino acid [aa] identity) with YadA of Yersinia enterocolitica and Eib, a recently described phage-encoded immunoglobulin binding protein from E. coli. Saa produced by 98NK2 is 516 aa long and includes four copies of a 37-aa direct repeat sequence. Interestingly, Saa produced by other STEC strains ranges in size from 460 to 534 aa as a consequence of variation in the number of repeats and/or other insertions or deletions immediately proximal to the repeat domain.
Keywords: Tumor Cells, Cultured
Mice, Inbred BALB C
Escherichia coli
Escherichia coli Infections
Adhesins, Bacterial
Escherichia coli Proteins
DNA, Bacterial
Shiga Toxin
Antibodies, Bacterial
Cloning, Molecular
Sequence Analysis, DNA
Gene Expression
Amino Acid Sequence
Base Sequence
Sequence Homology, Amino Acid
Genetic Heterogeneity
Genes, Bacterial
Molecular Sequence Data
Description: Copyright © 2001 by the American Society for Microbiology. All rights reserved.
DOI: 10.1128/IAI.69.11.6999-7009.2001
Appears in Collections:Aurora harvest 6
Molecular and Biomedical Science publications

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