title: Adhesion patterns of commensal and pathogenic Escherichia coli from humans and wild animals on human and porcine epithelial cell lines.
abstract: BACKGROUND
  Different strategies of colonization or infection by E. coli result in formation of certain adhesion patterns which help also in classifying intestinal E. coli into pathotypes. Little is known about adhesion patterns and host- and tissue adaption of commensal E. coli and about E. coli originating in clinically healthy hosts carrying pathotype-specific virulence-associated genes.
  
  
  RESULTS
  Adhesion pattern of E. coli (n = 282) from humans and from 18 animal species were verified on intestinal human Caco-2 and porcine IPEC-J2 cells and, furthermore, for comparison on human urinary bladder 5637, porcine kidney PK-15 epithelial and HEp-2 cells. The analysis was carried out on 150,000 images of adhesion assays.Adhesion patterns were very diverse; 88 isolates were completely non-adherent, whereas 194 adhered to at least one cell line with the dominant adhesion patterns "diffusely distributed" and "microcolony formation". Adhesion patterns "chains" and "clumps" were also visible. Chain formation was mediated by the presence of epithelial cells. Clump formation was very specific on only the 5637 cell line. All enteropathogenic (eae+) E. coli (EPEC; n = 14) were able to form microcolonies which was cell line specific for each isolate. Most EPEC formed microcolonies on intestinal IPEC-J2 and Caco-2 but several also on urinary tract cells. Shigatoxin-producing (stx+) E. coli (n = 10) showed no specific adhesion patterns.
  
  
  CONCLUSIONS
  E. coli isolates were highly diverse. Commensal and pathogenic isolates can adhere in various forms, including diffuse distribution, microcolonies, chains and clumps. Microcolony formation seems to be a global adhesion strategy also for commensal E. coli.
authors.affiliation: Brandenburg Technical University Cottbus/Senftenberg, Faculty of Natural Sciences, Großenhainer Str, 57, D-01968, Senftenberg, Germany. ulrike.froemmel@gmx.de.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Frömmel
authors.forename: Alexander
authors.initials: A
authors.lastname: Böhm
authors.forename: Jörg
authors.initials: J
authors.lastname: Nitschke
authors.forename: Jörg
authors.initials: J
authors.lastname: Weinreich
authors.forename: Julia
authors.initials: J
authors.lastname: Groß
authors.forename: Stefan
authors.initials: S
authors.lastname: Rödiger
authors.forename: Thomas
authors.initials: T
authors.lastname: Wex
authors.forename: Hermann
authors.initials: H
authors.lastname: Ansorge
authors.forename: Olaf
authors.initials: O
authors.lastname: Zinke
authors.forename: Christian
authors.initials: C
authors.lastname: Schröder
authors.forename: Dirk
authors.initials: D
authors.lastname: Roggenbuck
authors.forename: Peter
authors.initials: P
authors.lastname: Schierack