Enterotoxigenic<i><i>Escherichia coli</i></i>

Fleckenstein, James M.; Munson, George P.; Rasko, David A.

doi:10.4161/gmic.25861

Cited by 21 publications

(10 citation statements)

References 44 publications

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“…Nonclassic adhesins include representatives of various autotransporter families, such as TibA, a member of the adhesin involved in diffuse adherence (AIDA-I) family, and EtpA, part of a two-partner secretion system (12,13). A lack of knowledge regarding the heterogeneity of ETEC strains, which rely on different repertoires of adhesins, O antigens, and toxins, has been a barrier to developing a vaccine to prevent infection (14,15). This paper describes the newly identified gene, tleA, which codes for a homologue of the autotransporter Tsh, a member of the SPATE (serine protease autotransporter of Enterobacteriaceae) family described previously in avian pathogenic Escherichia coli (APEC) strains.…”

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confidence: 99%

TleA, a Tsh-Like Autotransporter Identified in a Human Enterotoxigenic Escherichia coli Strain

et al. 2015

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e Enterotoxigenic Escherichia coli (ETEC), a leading cause of acute diarrhea, colonizes the intestine by means of adhesins. However, 15 to 50% of clinical isolates are negative for known adhesins, making it difficult to identify antigens for broad-coverage vaccines. The ETEC strain 1766a, obtained from a child with watery diarrhea in Chile, harbors the colonization factor CS23 but is negative for other known adhesins. One clone, derived from an ETEC 1766a genomic library (clone G10), did not produce CS23 yet was capable of adhering to Caco-2 cells. The goal of this study was to identify the gene responsible for this capacity. Random transposon-based mutagenesis allowed the identification of a 4,110-bp gene that codes for a homologue of the temperature-sensitive hemagglutinin (Tsh) autotransporter described in avian E. coli strains (97% identity, 90% coverage) and that is called TleA (Tsh-like ETEC autotransporter) herein. An isogenic ETEC 1766a strain with a tleA mutation showed an adhesion level similar to that of the wild-type strain, suggesting that the gene does not direct attachment to Caco-2 cells. However, expression of tleA conferred the capacity for adherence to nonadherent E. coli HB101. This effect coincided with the detection of TleA on the surface of nonpermeabilized bacteria, while, conversely, ETEC 1766a seems to secrete most of the produced autotransporter to the medium. On the other hand, TleA was capable of degrading bovine submaxillary mucin and leukocyte surface glycoproteins CD45 and P-selectin glycoprotein ligand 1 (PSGL-1). These results suggest that TleA promotes colonization of the intestinal epithelium and that it may modulate the host immune response.

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confidence: 99%

TleA, a Tsh-Like Autotransporter Identified in a Human Enterotoxigenic Escherichia coli Strain

et al. 2015

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“…Enterotoxigenic E. coli strains are a significant aetiological agent of diarrhoeal disease worldwide (Fleckenstein et al ., ). The present study presents dairy products as a potential transmission vehicle of these pathogenic strains.…”

Section: Discussionmentioning

confidence: 98%

Molecular characterisation and stress tolerance of Escherichia coli isolated from dairy and dried milk‐related products

El-Sharoud

Yassin

Ahmed

2014

Int J of Food Sci Tech

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Summary This study characterised the phylogenetic groups, pathotypes, antibiotic resistance and stress response of Escherichia coli isolates recovered from dairy and dried milk‐related products. A total of 54 isolates of E. coli were recovered from thirty‐three of 180 samples (18%) of these products. Representatives from all the four phylogenetic groups of the organism were identified, although groups A and B1 dominated groups B2 and D. Enterotoxigenic E. coli (ETEC) strains producing heat‐labile toxin (LT) could be detected among the isolates and were found to be associated with the Kariesh cheese. Escherichia coli isolates showed single‐drug and multiple‐drug resistance to ß‐lactams and other antibiotic classes. The blaTEM‐1 gene was found to be associated with resistance to ampicillin but not to cephalothin. Escherichia coli survived heating at 50 and 55 °C for 60 min, but was undetectable after only 10 min of exposure to 60 °C. It also survived in the presence of 6% and 8% salt for 96 h and in pH 4.0 for 72 h.

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“…However, the antigenic diversity of the CFs and the possibility that other molecules may participate in intestinal colonization and toxin delivery have prompted efforts to define additional target antigens that might augment existing approaches. Recent studies provide compelling evidence that the molecular pathogenesis of ETEC is more complex than had been appreciated previously and that a number of novel surface or secreted virulence proteins could serve as viable targets for future development efforts (53).…”

Section: Discussionmentioning

confidence: 99%

Contribution of the Highly Conserved EaeH Surface Protein to Enterotoxigenic Escherichia coli Pathogenesis

Sheikh

Luo

Roy³

et al. 2014

Infect Immun

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f Enterotoxigenic Escherichia coli (ETEC) strains are among the most common causes of diarrheal illness worldwide. These pathogens disproportionately afflict children in developing countries, where they cause substantial morbidity and are responsible for hundreds of thousands of deaths each year. Although these organisms are important targets for enteric vaccines, most development efforts to date have centered on a subset of plasmid-encoded fimbrial adhesins known as colonization factors and heatlabile toxin (LT). Emerging data suggest that ETEC undergoes considerable changes in its surface architecture, sequentially deploying a number of putative adhesins during its interactions with the host. We demonstrate here that one putative highly conserved, chromosomally encoded adhesin, EaeH, engages the surfaces of intestinal epithelial cells and contributes to bacterial adhesion, LT delivery, and colonization of the small intestine. Infectious diarrhea continues to cause tremendous suffering in developing countries, resulting in an estimated one to two million deaths each year. Enterotoxigenic Escherichia coli (ETEC) contributes significantly to premature deaths from diarrheal illness in young children (1, 2) and causes substantial morbidity in surviving children and adults (3). ETEC strains are perennially the leading etiology of diarrhea in travelers to areas where ETEC strains are endemic (4).By definition, these organisms secrete heat-labile (LT) and/or heat-stable (ST) enterotoxins that induce host cell production of cyclic nucleotides (cyclic AMP [cAMP] and cGMP, respectively) to activate protein kinases that ultimately result in phosphorylation of the cystic fibrosis transmembrane regulatory channel (CFTR) (5-7) and Na ϩ ion exchangers (8) on the surfaces of intestinal epithelial cells. Ensuing chloride secretion through CFTR, as well as the commensurate loss of salt and water into the intestinal lumen, results in the cholera-like watery diarrhea characteristic of ETEC infections (9).In the current paradigm for ETEC pathogenesis, this organism must effectively colonize the small intestine to deliver LT and/or ST efficiently. The majority of pathogenesis (10-12) and molecular epidemiology (13) studies, as well as subsequent vaccine development efforts (14, 15), have focused primarily on plasmid-encoded fimbrial colonization factors (CFs), which are felt to be critical for colonization of the small intestine.This longstanding but fairly simple view of ETEC pathogenesis in which bacteria adhere via CFs to the small intestine, where these pathogens release their toxin(s), likely underestimates the complexity of these pathogens. More recent investigations have highlighted a number of novel putative virulence factors (16, 17), unique interactions of ETEC with the epithelium (18)(19)(20), and an intricate orchestration of multiple pathogen-host events (21) that culminate in successful toxin delivery to epithelial cell targets (22). Collectively, the emerging data suggest that these sophisticated interactions of ETEC ...

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EnterotoxigenicEscherichia coli

Cited by 21 publications

References 44 publications

TleA, a Tsh-Like Autotransporter Identified in a Human Enterotoxigenic Escherichia coli Strain

TleA, a Tsh-Like Autotransporter Identified in a Human Enterotoxigenic Escherichia coli Strain

Molecular characterisation and stress tolerance of Escherichia coli isolated from dairy and dried milk‐related products

Contribution of the Highly Conserved EaeH Surface Protein to Enterotoxigenic Escherichia coli Pathogenesis

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