title: Human intestinal tissue tropism in Escherichia coli O157 : H7--initial colonization of terminal ileum and Peyer's patches and minimal colonic adhesion ex vivo.
abstract: Enterohaemorrhagic Escherichia coli (EHEC) are an important cause of diarrhoeal and renal disease in man. Studies of a single prototypic O157 : H7 strain have shown tropism for follicle-associated epithelium (FAE) of distal ileal Peyer's patches without colonization of either small or large intestine. This study determined tropism in a range of Shiga toxin (Stx)-negative EHEC strains and looked for factors that might induce colonic colonization using human in vitro intestinal organ culture (IVOC). An FAE-restricted colonization was confirmed in two strains; four strains additionally colonized ileal villous surfaces, and adhesion to proximal small intestinal FAE was observed. All strains showed minimal adhesion to non-FAE regions of proximal small intestinal and to the transverse colon. Extensive large-bowel IVOC studies using three O157 : H7 strains, an O26 : H11 and an O103 : H2 strain, and tissue from caecum to rectum found colonization and attaching/effacing lesion formation in only 4 of 113 (3.5 %) IVOCs. Colonic adhesion was not enhanced by altering the IVOC technique or environment. Co-incubation of O157 : H7-infected ileal FAE with colonic samples enhanced colonic colonization, producing a novel, non-intimate adhesive phenotype. Thus, in the initial stages of colonization Stx-negative EHEC preferentially infect FAE and villi of the terminal ileal region ex vivo; colonic colonization is infrequently observed as an initial event but may represent a subsequent stage of infection.
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free Hospital, Imperial College, London, UK.
authors.forename: Yuwen
authors.initials: Y
authors.lastname: Chong
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free Hospital, Imperial College, London, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Fitzhenry
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free Hospital, Imperial College, London, UK.
authors.forename: Robert
authors.initials: R
authors.lastname: Heuschkel
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free Hospital, Imperial College, London, UK.
authors.forename: Franco
authors.initials: F
authors.lastname: Torrente
authors.affiliation: Division of Cell and Molecular Biology, Imperial College, London, UK.
authors.forename: Gad
authors.initials: G
authors.lastname: Frankel
authors.affiliation: Centre for Paediatric Gastroenterology, Royal Free Hospital, Imperial College, London, UK.
authors.forename: Alan D
authors.initials: AD
authors.lastname: Phillips
mesh_terms: D001422:Bacterial Adhesion; D002460:Cell Line; D003106:Colon / Q000382:microbiology*; D004927:Escherichia coli Infections / Q000382:microbiology*; D019453:Escherichia coli O157 / Q000502:physiology*; D006801:Humans; D007082:Ileum / Q000382:microbiology*; D008855:Microscopy, Electron, Scanning; D009924:Organ Culture Techniques; D010581:Peyer's Patches / Q000382:microbiology*; D022621:Shiga Toxin / Q000096:biosynthesis / Q000235:genetics
chemical_list: D022621:Shiga Toxin