scholarly journals A New Immunoglobulin-Binding Protein, EibG, Is Responsible for the Chain-Like Adhesion Phenotype of Locus of Enterocyte Effacement-Negative, Shiga Toxin-Producing Escherichia coli

2006 ◽  
Vol 74 (10) ◽  
pp. 5747-5755 ◽  
Author(s):  
Yan Lu ◽  
Sunao Iyoda ◽  
Hiromi Satou ◽  
Hitomi Satou ◽  
Kenichiro Itoh ◽  
...  

ABSTRACT Shiga toxin-producing Escherichia coli (STEC) are important enteropathogens causing severe diseases such as hemorrhagic colitis and hemolytic-uremic syndrome in humans. The majority of STEC strains of serogroups O157, O26, or O111 associated with severe cases of these diseases possess a pathogenicity island termed the locus of enterocyte effacement (LEE). LEE, which is responsible for the formation of attaching-and-effacing lesions on intestinal epithelial cells, is important for the full virulence of STEC. Nonetheless, LEE-negative STEC strains have repeatedly been reported to be associated with severe diseases in humans. In this study, we characterized adhesion to cultured epithelial cells of certain LEE-negative STEC isolated from humans with or without bloody diarrhea. Several LEE-negative STEC belonging to serogroup O91 showed an unusual, chain-like adhesion pattern to HEp-2 cells. Using Tn5-based transposon mutagenesis, we identified the gene essential for the chain-like adhesion phenotype of this O91 STEC strain. Sequence analysis of the Tn5-inserted allele identified a novel chromosomal open reading frame (ORF) encoding a polypeptide with a high degree of similarity to the E. coli immunoglobulin-binding (Eib) proteins EibA, -C, -D, -E, and -F. Therefore, the ORF was designated EibG. Laboratory E. coli strain MC4100 transformed with a multicopy plasmid carrying eibG showed chain-like adhesion to HEp-2 cells, and whole-cell lysates of the strain bound to human-derived immunoglobulin G (IgG) Fc and IgA. These results indicate that EibG acts as an IgG Fc- and IgA-binding protein, as well as an adhesin of LEE-negative STEC.

2010 ◽  
Vol 78 (8) ◽  
pp. 3625-3636 ◽  
Author(s):  
Viktor Merkel ◽  
Barbara Ohder ◽  
Martina Bielaszewska ◽  
Wenlan Zhang ◽  
Angelika Fruth ◽  
...  

ABSTRACT eibG in Shiga toxin-producing Escherichia coli (STEC) O91 encodes a protein (EibG) which binds human immunoglobulins G and A and contributes to bacterial chain-like adherence to human epithelial cells. We investigated the prevalence of eibG among STEC, the phylogeny of eibG, and eibG allelic variations and their impact on the adherence phenotype. eibG was found in 15.0% of 240 eae-negative STEC strains but in none of 157 eae-positive STEC strains. The 36 eibG-positive STEC strains belonged to 14 serotypes and to eight multilocus sequence types (STs), with serotype O91:H14/H− and ST33 being the most common. Sequences of the complete eibG gene (1,527 bp in size) from eibG-positive STEC resulted in 21 different alleles with 88.11% to 100% identity to the previously reported eibG sequence; they clustered into three eibG subtypes (eibG-α, eibG-β, and eibG-γ). Strains expressing EibG-α and EibG-β displayed a mostly typical chain-like adherence pattern (CLAP), with formation of long chains on both human and bovine intestinal epithelial cells, whereas strains with EibG-γ adhered in short chains, a pattern we termed atypical CLAP. The same adherence phenotypes were displayed by E. coli BL21(DE3) clones containing the respective eibG-α, eibG-β, and eibG-γ subtypes. We propose two possible evolutionary scenarios for eibG in STEC: a clonal development of eibG in strains with the same phylogenetic background or horizontal transfer of eibG between phylogenetically unrelated STEC strains.


2017 ◽  
Vol 85 (12) ◽  
Author(s):  
Roslen Bondì ◽  
Paola Chiani ◽  
Valeria Michelacci ◽  
Fabio Minelli ◽  
Alfredo Caprioli ◽  
...  

ABSTRACT Locus of enterocyte effacement (LEE)-negative Shiga toxin (Stx)-producing Escherichia coli (STEC) strains are human pathogens that lack the LEE locus, a pathogenicity island (PAI) involved in the intimate adhesion of LEE-positive strains to the host gut epithelium. The mechanism used by LEE-negative STEC strains to colonize the host intestinal mucosa is still not clear. The cell invasion determinant tia, previously described in enterotoxigenic E. coli strains, has been identified in LEE-negative STEC strains that possess the subtilase-encoding pathogenicity island (SE-PAI). We evaluated the role of the gene tia, present in these LEE-negative STEC strains, in the invasion of monolayers of cultured cells. We observed that these strains were able to invade Caco-2 and HEp-2 cell monolayers and compared their invasion ability with that of a mutant strain in which the gene tia had been inactivated. Mutation of the gene tia resulted in a strong reduction of the invasive phenotype, and complementation of the tia mutation with a functional copy of the gene restored the invasion activity. Moreover, we show that the gene tia is overexpressed in bacteria actively invading cell monolayers, demonstrating that tia is involved in the ability to invade cultured monolayers of epithelial cells shown by SE-PAI-positive E. coli, including STEC, strains. However, the expression of the tia gene in the E. coli K-12 strain JM109 was not sufficient, in its own right, to confer to this strain the ability to invade cell monolayers, suggesting that at least another factor must be involved in the invasion ability displayed by the SE-PAI-positive strains.


2005 ◽  
Vol 71 (12) ◽  
pp. 8855-8863 ◽  
Author(s):  
Anne-Katharina Sonntag ◽  
Martina Bielaszewska ◽  
Alexander Mellmann ◽  
Nadine Dierksen ◽  
Peter Schierack ◽  
...  

ABSTRACT Thirteen Escherichia coli strains harboring stx 2e were isolated from 11,056 human stools. This frequency corresponded to the presence of the stx 2e allele in 1.7% of all Shiga toxin-producing E. coli (STEC) strains. The strains harboring stx 2e were associated with mild diarrhea (n = 9) or asymptomatic infections (n= 4). Because STEC isolates possessing stx 2e are porcine pathogens, we compared the human STEC isolates with stx 2e-harboring E. coli isolated from piglets with edema disease and postweaning diarrhea. All pig isolates possessed the gene encoding the F18 adhesin, and the majority possessed adhesin involved in diffuse adherence; these adhesins were absent from all the human STEC isolates. In contrast, the high-pathogenicity island encoding an iron uptake system was found only in human isolates. Host-specific patterns of interaction with intestinal epithelial cells were observed. All human isolates adhered to human intestinal epithelial cell lines T84 and HCT-8 but not to pig intestinal epithelial cell line IPEC-J2. In contrast, the pig isolates completely lysed human epithelial cells but not IPEC-J2 cells, to which most of them adhered. Our data demonstrate that E. coli isolates producing Shiga toxin 2e have imported specific virulence and fitness determinants which allow them to adapt to the specific hosts in which they cause various forms of disease.


2010 ◽  
Vol 78 (9) ◽  
pp. 4068-4076 ◽  
Author(s):  
Jennifer Hwang ◽  
Lisa M. Mattei ◽  
Laura G. VanArendonk ◽  
Philip M. Meneely ◽  
Iruka N. Okeke

ABSTRACT Enteroaggregative Escherichia coli (EAEC) strains are important diarrheal pathogens. EAEC strains are defined by their characteristic stacked-brick pattern of adherence to epithelial cells but show heterogeneous virulence and have different combinations of adhesin and toxin genes. Pathoadaptive deletions in the lysine decarboxylase (cad) genes have been noted among hypervirulent E. coli subtypes of Shigella and enterohemorrhagic E. coli. To test the hypothesis that cad deletions might account for heterogeneity in EAEC virulence, we developed a Caenorhabditis elegans pathogenesis model. Well-characterized EAEC strains were shown to colonize and kill C. elegans, and differences in virulence could be measured quantitatively. Of 49 EAEC strains screened for lysine decarboxylase activity, 3 tested negative. Most notable is isolate 101-1, which was recovered in Japan, from the largest documented EAEC outbreak. EAEC strain 101-1 was unable to decarboxylate lysine in vitro due to deletions in cadA and cadC, which, respectively, encode lysine decarboxylase and a transcriptional activator of the cadAB genes. Strain 101-1 was significantly more lethal to C. elegans than control strain OP50. Lethality was attenuated when the lysine decarboxylase defect was complemented from a multicopy plasmid and in single copy. In addition, restoring lysine decarboxylase function produced derivatives of 101-1 deficient in aggregative adherence to cultured human epithelial cells. Lysine decarboxylase inactivation is pathoadapative in an important EAEC outbreak strain, and deletion of cad genes could produce hypervirulent EAEC lineages in the future. These results suggest that loss, as well as gain, of genetic material can account for heterogeneous virulence among EAEC strains.


2012 ◽  
Vol 75 (2) ◽  
pp. 408-418 ◽  
Author(s):  
LOTHAR BEUTIN ◽  
ANNETT MARTIN

An outbreak that comprised 3,842 cases of human infections with enteroaggregative hemorrhagic Escherichia coli (EAHEC) O104:H4 occurred in Germany in May 2011. The high proportion of adults affected in this outbreak and the unusually high number of patients that developed hemolytic uremic syndrome makes this outbreak the most dramatic since enterohemorrhagic E. coli (EHEC) strains were first identified as agents of human disease. The characteristics of the outbreak strain, the way it spread among humans, and the clinical signs resulting from EAHEC infections have changed the way Shiga toxin–producing E. coli strains are regarded as human pathogens in general. EAHEC O104:H4 is an emerging E. coli pathotype that is endemic in Central Africa and has spread to Europe and Asia. EAHEC strains have evolved from enteroaggregative E. coli by uptake of a Shiga toxin 2a (Stx2a)–encoding bacteriophage. Except for Stx2a, no other EHEC-specific virulence markers including the locus of enterocyte effacement are present in EAHEC strains. EAHEC O104:H4 colonizes humans through aggregative adherence fimbrial pili encoded by the enteroaggregative E. coli plasmid. The aggregative adherence fimbrial colonization mechanism substitutes for the locus of enterocyte effacement functions for bacterial adherence and delivery of Stx2a into the human intestine, resulting clinically in hemolytic uremic syndrome. Humans are the only known natural reservoir known for EAHEC. In contrast, Shiga toxin–producing E. coli and EHEC are associated with animals as natural hosts. Contaminated sprouted fenugreek seeds were suspected as the primary vehicle of transmission of the EAHEC O104:H4 outbreak strain in Germany. During the outbreak, secondary transmission (human to human and human to food) was important. Epidemiological investigations revealed fenugreek seeds as the source of entry of EAHEC O104:H4 into the food chain; however, microbiological analysis of seeds for this pathogen produced negative results. The survival of EAHEC in seeds and the frequency of human carriers of EAHEC should be investigated for a better understanding of EAHEC transmission routes.


2019 ◽  
Vol 29 (1-6) ◽  
pp. 91-100
Author(s):  
Dorna Khoobbakht ◽  
Shohreh Zare Karizi ◽  
Mohammad Javad  Motamedi ◽  
Rouhollah Kazemi ◽  
Pooneh Roghanian ◽  
...  

Enterotoxigenic <i>Escherichia coli</i> (ETEC) is the most common agent of diarrhea morbidity in developing countries. ETEC adheres to host intestinal epithelial cells via various colonization factors. The CooD and CotD proteins play a significant role in bacteria binding to the intestinal epithelial cells as adhesin tip subunits of CS1 and CS2 pili. The purpose here was to design a new construction containing <i>cooD</i> and <i>cotD</i> genes and use several types of bioinformatics software to predict the structural and immunological properties of the designed antigen. The fusion gene was synthesized with codon bias of <i>E. coli</i> in order to increase the expression level of the protein. The amino acid sequences, protein structure, and immunogenicity properties of potential antigens were analyzed in silico. The chimeric protein was expressed in <i>E. coli</i>BL21 (DE3). The antigenicity of the recombinant proteins was verified by Western blotting and ELISA. In order to assess the induced immunity, the immunized mice were challenged with wild-type ETEC by an intraperitoneal route. Immunological analyses showed the production of a high titer of IgG serum with no sign of serum-mucosal IgA antibody response. The result of the challenge assay showed that 30% of immunized mice survived. The results of this study showed that CooD-CotD recombinant protein can stimulate immunity against ETEC. The designed chimera could be a prototype for the subunit vaccine, which is worthy of further consideration.


2000 ◽  
Vol 68 (3) ◽  
pp. 1400-1407 ◽  
Author(s):  
Phillip I. Tarr ◽  
Sima S. Bilge ◽  
James C. Vary ◽  
Srdjan Jelacic ◽  
Rebecca L. Habeeb ◽  
...  

ABSTRACT The mechanisms used by Shiga toxin (Stx)-producingEscherichia coli to adhere to epithelial cells are incompletely understood. Two cosmids from an E. coliO157:H7 DNA library contain an adherence-conferring chromosomal gene encoding a protein similar to iron-regulated gene A (IrgA) ofVibrio cholerae (M. B. Goldberg, S. A. Boyko, J. R. Butterton, J. A. Stoebner, S. M. Payne, and S. B. Calderwood, Mol. Microbiol. 6:2407–2418, 1992). We have termed the product of this gene the IrgA homologue adhesin (Iha), which is encoded by iha. Iha is 67 kDa in E. coliO157:H7 and 78 kDa in laboratory E. coli and is structurally unlike other known adhesins. DNA adjacent toiha contains tellurite resistance loci and is conserved in structure in distantly related pathogenic E. coli, but it is absent from nontoxigenic E. coli O55:H7, sorbitol-fermenting Stx-producing E. coli O157:H−, and laboratory E. coli. We have termed this region the tellurite resistance- and adherence-conferring island. We conclude that Iha is a novel bacterial adherence-conferring protein and is contained within an E. coli chromosomal island of conserved structure. Pathogenic E. coli O157:H7 has only recently acquired this island.


Digestion ◽  
2014 ◽  
Vol 89 (2) ◽  
pp. 110-118 ◽  
Author(s):  
Helen M. Becker ◽  
Aretussa Apladas ◽  
Michael Scharl ◽  
Michael Fried ◽  
Gerhard Rogler

2009 ◽  
Vol 75 (18) ◽  
pp. 5927-5937 ◽  
Author(s):  
Brandon A. Carlson ◽  
Kendra K. Nightingale ◽  
Gary L. Mason ◽  
John R. Ruby ◽  
W. Travis Choat ◽  
...  

ABSTRACT A longitudinal study was conducted to investigate the nature of Escherichia coli O157:H7 colonization of feedlot cattle over the final 100 to 110 days of finishing. Rectal fecal grab samples were collected from an initial sample population of 788 steers every 20 to 22 days and microbiologically analyzed to detect E. coli O157:H7. The identities of presumptive colonies were confirmed using a multiplex PCR assay that screened for gene fragments unique to E. coli O157:H7 (rfbE and fliC h7) and other key virulence genes (eae, stx 1, and stx 2). Animals were classified as having persistent shedding (PS), transient shedding (TS), or nonshedding (NS) status if they consecutively shed the same E. coli O157:H7 genotype (based on the multiplex PCR profile), exhibited variable E. coli O157 shedding, or never shed morphologically typical E. coli O157, respectively. Overall, 1.0% and 1.4% of steers were classified as PS and NS animals, respectively. Characterization of 132 E. coli O157:H7 isolates from PS and TS animals by pulsed-field gel electrophoresis (PFGE) typing yielded 32 unique PFGE types. One predominant PFGE type accounted for 53% of all isolates characterized and persisted in cattle throughout the study. Isolates belonging to this predominant and persistent PFGE type demonstrated an enhanced (P < 0.0001) ability to adhere to Caco-2 human intestinal epithelial cells compared to isolates belonging to less common PFGE types but exhibited equal virulence expression. Interestingly, the attachment efficacy decreased as the genetic divergence from the predominant and persistent subtype increased. Our data support the hypothesis that certain E. coli O157:H7 strains persist in feedlot cattle, which may be partially explained by an enhanced ability to colonize the intestinal epithelium.


2001 ◽  
Vol 69 (9) ◽  
pp. 5679-5688 ◽  
Author(s):  
Ivana Simonovic ◽  
Monique Arpin ◽  
Athanasia Koutsouris ◽  
Holly J. Falk-Krzesinski ◽  
Gail Hecht

ABSTRACT Enteropathogenic Escherichia coli (EPEC) is an important human intestinal pathogen, especially in infants. EPEC adherence to intestinal epithelial cells induces the accumulation of a number of cytoskeletal proteins beneath the bacteria, including the membrane-cytoskeleton linker ezrin. Evidence suggests that ezrin can participate in signal transduction. The aim of this study was to determine whether ezrin is activated following EPEC infection and if it is involved in the cross talk with host intestinal epithelial cells. We show here that following EPEC attachment to intestinal epithelial cells there was significant phosphorylation of ezrin, first on threonine and later on tyrosine residues. A significant increase in cytoskeleton-associated ezrin occurred following phosphorylation, suggesting activation of this molecule. Nonpathogenic E. coli and EPEC strains harboring mutations in type III secretion failed to elicit this response. Expression of dominant-negative ezrin significantly decreased the EPEC-elicited association of ezrin with the cytoskeleton and attenuated the disruption of intestinal epithelial tight junctions. These results suggest that ezrin is involved in transducing EPEC-initiated signals that ultimately affect host physiological functions.


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