title: Distinct binding properties of eaeA-negative verocytotoxin-producing Escherichia coli of serotype O113:H21.
abstract: Infection of humans with verotoxin-producing Escherichia coli (VTEC) O113:H21 is associated with clinical features comparable to those associated with infection with attaching and effacing VTEC strains including those of serotype O157:H7. We have shown previously that the adhesion phenotype of VTEC O157:H7 is influenced by the presence of a homolog of the chromosomal eaeA (for E. coli attaching and effacing) gene. In contrast, by colony blot hybridization, VTEC O113:H21 is negative for the eaeA gene. Therefore, the aim of this study was to define the adhesion phenotype of VTEC O113:H21 strain CL-15 to both cultured epithelial cells (HEp-2) and rabbit intestine in vivo. Under transmission electron microscopy, areas of microvillus effacement were observed in regions directly beneath the organism in CL-15-infected cells both in vitro and in vivo. However, F-actin adhesion pedestals on the host plasma membrane were absent. Failure of CL-15 to induce polymerization of actin was confirmed by using staining of F-actin with fluorescein-labeled phalloidin. Under indirect immunofluorescence microscopy, CL-15-infected HEp-2 cells also failed to demonstrate the recruitment of another cytoskeletal element, alpha-actinin, below foci of bacterial adhesion. In contrast, VTEC O157:H7 infection of HEp-2 cells was associated with increased alpha-actinin immunofluorescence. These findings suggest that bacterial factors distinct from those of EaeA are necessary for the adhesion phenotype of VTEC O113:H21.
authors.affiliation: Division of Gastroenterology, Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: M T
authors.initials: MT
authors.lastname: Dytoc
authors.forename: A
authors.initials: A
authors.lastname: Ismaili
authors.forename: D J
authors.initials: DJ
authors.lastname: Philpott
authors.forename: R
authors.initials: R
authors.lastname: Soni
authors.forename: J L
authors.initials: JL
authors.lastname: Brunton
authors.forename: P M
authors.initials: PM
authors.lastname: Sherman
mesh_terms: D000185:Actinin / Q000378:metabolism; D018829:Adhesins, Bacterial; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000633:toxicity*; D002352:Carrier Proteins; D004926:Escherichia coli / Q000235:genetics / Q000472:pathogenicity*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006801:Humans; D019000:Phosphotyrosine; D022622:Shiga Toxin 1; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D014774:Virulence
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001427:Bacterial Toxins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D022622:Shiga Toxin 1; D000185:Actinin; C073819:eaeA protein, E coli; D019000:Phosphotyrosine; D014443:Tyrosine