title: Adherence of Escherichia coli O157:H7 mutants in vitro and in ligated pig intestines.
abstract: There are contradictory literature reports on the role of verotoxin (VT) in adherence of enterohemorrhagic Escherichia coli O157:H7 (O157 EHEC) to intestinal epithelium. There are reports that putative virulence genes of O island 7 (OI-7), OI-15, and OI-48 of this pathogen may also affect adherence in vitro. Therefore, mutants of vt2 and segments of OI-7 and genes aidA(15) (gene from OI-15) and aidA(48) (gene from OI-48) were generated and evaluated for adherence in vitro to cultured human HEp-2 and porcine jejunal epithelial (IPEC-J2) cells and in vivo to enterocytes in pig ileal loops. VT2-negative mutants showed significant decreases in adherence to both HEp-2 and IPEC-J2 cells and to enterocytes in pig ileal loops; complementation only partially restored VT2 production but fully restored the adherence to the wild-type level on cultured cells. Deletion of OI-7 and aidA(48) had no effect on adherence, whereas deletion of aidA(15) resulted in a significant decrease in adherence in pig ileal loops but not to the cultured cells. This investigation supports the findings that VT2 plays a role in adherence, shows that results obtained in adherence of E. coli O157:H7 in vivo may differ from those obtained in vitro, and identified AIDA-15 as having a role in adherence of E. coli O157:H7.
authors.affiliation: Guelph Food Research Centre, Ontario, Canada.
authors.forename: Xianhua
authors.initials: X
authors.lastname: Yin
authors.forename: James R
authors.initials: JR
authors.lastname: Chambers
authors.forename: Roger
authors.initials: R
authors.lastname: Wheatcroft
authors.forename: Roger P
authors.initials: RP
authors.lastname: Johnson
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Bianfang
authors.initials: B
authors.lastname: Liu
authors.forename: Carlton L
authors.initials: CL
authors.lastname: Gyles
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D002460:Cell Line; D020895:Enterocytes / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D005816:Genetic Complementation Test; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D022641:Shiga Toxin 2 / Q000235:genetics; D013552:Swine; D037521:Virulence Factors / Q000235:genetics
chemical_list: D022641:Shiga Toxin 2; D037521:Virulence Factors