Afa, a Diffuse Adherence Fibrillar Adhesin Associated with Enteropathogenic
            <i>Escherichia coli</i>

Keller, Rogéria; Ordonez, Juana; Oliveira, R.; Trabulsi, Luíz Rachid; Baldwin, Thomas J.; Knutton, Stuart

doi:10.1128/iai.70.5.2681-2689.2002

Cited by 43 publications

(31 citation statements)

References 30 publications

(15 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These findings indicate that environmental and eukaryotic cell factors are stimulating the expressions of different adherence patterns. Among the strains analyzed in this study, AA and DA patterns are mediated by specific adhesins expressed by strains Ec292/84 and 9100/83, respectively (5,29), and the LAL pattern of strain BA320 is probably mediated by intimin and EspA, as suggested by the analysis of a bundle-forming pilus (BFP) mutant of tEPEC strain E2348/69 (10). It is interesting that the incapacity of strain BA4013 to adhere to HEp-2 cells was also observed for intestinal cells, which resemble the human intestinal environment.…”

Section: Discussionmentioning

confidence: 99%

“…The four aEPEC strains were isolated from cases of acute diarrhea and previously characterized by HEp-2 cell adherence assays as displaying the LAL (strain BA320), AA (strain Ec292/84), and DA (strain 9100/83) patterns and as being unable to adhere (strain BA4013) (1,5,29). Also, by means of the fluorescent actin staining (FAS) test, the strains were previously classified as being FAS positive (strains BA320 and 9100/83) and FAS negative (strains Ec292/84 and BA4013) (1,5,29). Bacterial strains were aerobically grown in Luria-Bertani (LB) broth or Dulbecco's modified Eagle medium (DMEM) at 37°C for 18 h unless otherwise stated.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Atypical Enteropathogenic Escherichia coli That Contains Functional Locus of Enterocyte Effacement Genes Can Be Attaching-and-Effacing Negative in Cultured Epithelial Cells

et al. 2011

View full text Add to dashboard Cite

Enteropathogenic Escherichia coli (EPEC) induces a characteristic histopathology on enterocytes known as the attaching-and-effacing (A/E) lesion, which is triggered by proteins encoded by the locus of enterocyte effacement (LEE). EPEC is currently classified as typical EPEC (tEPEC) and atypical EPEC (aEPEC), based on the presence or absence of the EPEC adherence factor plasmid, respectively. Here we analyzed the LEE regions of three aEPEC strains displaying the localized adherence-like (LAL), aggregative adherence (AA), and diffuse adherence (DA) patterns on HEp-2 cells as well as one nonadherent (NA) strain. The adherence characteristics and the ability to induce A/E lesions were investigated with HeLa, Caco-2, T84, and HT29 cells. The adherence patterns and fluorescent actin staining (FAS) assay results were reproducible with all cell lines. The LEE region was structurally intact and functional in all strains regardless of their inability to cause A/E lesions. An EspF U -expressing plasmid (pKC471) was introduced into all strains, demonstrating no influence of this protein on either the adherence patterns or the capacity to cause A/E of the adherent strains. However, the NA strain harboring pKC471 expressed the LAL pattern and was able to induce A/E lesions on HeLa cells. Our data indicate that FAS-negative aEPEC strains are potentially able to induce A/E in vivo, emphasizing the concern about this test for the determination of aEPEC virulence. Also, the presence of EspF U was sufficient to provide an adherent phenotype for a nonadherent aEPEC strain via the direct or indirect activation of the LEE4 and LEE5 operons.Diarrheal diseases are responsible for about 2 million deaths of children all over the world per year, mainly in developing countries (7). Enteropathogenic Escherichia coli (EPEC) is among the leading agents of acute infantile diarrhea (25,28,57). EPEC has been classified into two subgroups, named typical EPEC (tEPEC) and atypical EPEC (aEPEC), based on the presence or absence of the EPEC adherence factor plasmid (pEAF), respectively (27).The hallmark of EPEC pathogenesis is the ability to cause the attaching-and-effacing (A/E) lesion, which results from intimate bacterial adhesion to the intestinal epithelium, the effacement of local microvilli, and the accumulation of polymerized actin and other cytoskeleton elements at the site of bacterial attachment, forming pedestal-like structures (42). The capacity to cause A/E in vitro can be verified by the fluorescent actin staining (FAS) test, which detects polymerized actin aggregation at the site of bacterial attachment (33).A/E lesion-related genes are located in a pathogenicity island named the locus of enterocyte effacement (LEE) (28, 38).The LEE is organized into 5 operons (LEE1 to LEE5), where LEE1 to LEE3 encode type III secretion system (T3SS) proteins and the LEE-encoded regulator (Ler) (18,40), LEE4 encodes the secreted proteins that form the external part of the T3SS used to translocate effector proteins to the host cell, and LEE5 encodes th...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Atypical Enteropathogenic Escherichia coli That Contains Functional Locus of Enterocyte Effacement Genes Can Be Attaching-and-Effacing Negative in Cultured Epithelial Cells

et al. 2011

View full text Add to dashboard Cite

show abstract

“…24,25 However, more recent data question the existence of true afimbrial CU organelles. EM imaging of immunogold-labelled AfaE subunits has shown the filamentous nature of Afa/Dr adhesins 26,27 and biochemical studies on the Y. pestis F1 capsular antigen showed Caf1 fimbrial subunits organise into linear fibres through a donor-strand complementation mechanism. 28 Indeed, crystallographic analysis and NMR of FGL-system subunits [Y. pestis F1 capsular antigen, E. coli Afa/Dr adhesins and Salmonella enterica atypical fimbriae (Saf) pili] later revealed they share the incomplete Ig-like fold typical for CU pilus subunits and interact with one another or their respective chaperones via strand complementation.…”

Section: Introductionmentioning

confidence: 98%

Structural Analysis of the Saf Pilus by Electron Microscopy and Image Processing

Salih¹,

Remaut²,

Waksman

et al. 2008

Journal of Molecular Biology

View full text Add to dashboard Cite

“…The results were identical to those seen with the null mutant, LDA1 (data not shown). The appearance of LDA is very similar to that seen with other afimbrial adhesins, such as Ral from rabbit EPEC (1), CS6 from ETEC (56), and Afa, originally identified in a uropathogenic E. coli serotype O2 strain (26) and later in EPEC strain 132/12 (O55:H Ϫ ) (24). Thus, despite the amino acid homologies to the K88 and CS3A1 fimbriae, LDA appears to be afimbrial in structure.…”

Section: Identification and Cloning Of A Locus For Diffuse Adherencementioning

confidence: 67%

Identification and Characterization of the Locus for Diffuse Adherence, Which Encodes a Novel Afimbrial Adhesin Found in Atypical EnteropathogenicEscherichia coli

et al. 2005

View full text Add to dashboard Cite

The O26 serogroup of enteropathogenic Escherichia coli (EPEC) is one of the serogroups most frequently implicated in infant diarrhea and is also common among enterohemorrhagic E. coli (EHEC) strains. The most common O26 strains belong to EPEC/EHEC serotype O26:H11 and are generally Shiga toxin (Stx) positive. Stx-negative E. coli strains that are negative for the EPEC EAF plasmid and bundle-forming pilus (Bfp) are classified as atypical EPEC. Here, we report a novel adhesin present in an stx-negative bfpA-negative atypical EPEC O26:H11 strain isolated from an infant with diarrhea. A cloned 15-kb genomic region from this strain, designated the locus for diffuse adherence (lda), confers diffuse adherence on HEp-2 cells when expressed in E. coli K-12. Sequence analysis of lda revealed a G؉C content of 46.8% and 15 open reading frames sharing homology with the E. coli K88 fae and CS31A clp fimbrial operons. The lda region is part of a putative 26-kb genomic island inserted into the proP gene of the E. coli chromosome. Hybridization studies have demonstrated the prevalence of the minor structural subunit gene, ldaH, across E. coli serogroups O5, O26, O111, and O145. A second plasmid-encoded factor that contributed to the Hep-2 adherence of this strain was also identified but was not characterized. Null mutations that abolish adherence to HEp-2 cells can be restored by plasmid complementation. Antiserum raised against the major structural subunit, LdaG, recognizes a 25-kDa protein from crude heat-extracted protein preparations and inhibits the adherence of the E. coli DH5␣ lda ؉ clone to HEp-2 cells. Electron microscopy revealed a nonfimbrial structure surrounding the bacterial cell.

show abstract

Afa, a Diffuse Adherence Fibrillar Adhesin Associated with Enteropathogenic Escherichia coli

Cited by 43 publications

References 30 publications

Atypical Enteropathogenic Escherichia coli That Contains Functional Locus of Enterocyte Effacement Genes Can Be Attaching-and-Effacing Negative in Cultured Epithelial Cells

Atypical Enteropathogenic Escherichia coli That Contains Functional Locus of Enterocyte Effacement Genes Can Be Attaching-and-Effacing Negative in Cultured Epithelial Cells

Structural Analysis of the Saf Pilus by Electron Microscopy and Image Processing

Identification and Characterization of the Locus for Diffuse Adherence, Which Encodes a Novel Afimbrial Adhesin Found in Atypical EnteropathogenicEscherichia coli

Contact Info

Product

Resources

About