title: Intestinal mucosa adherence and cytotoxicity of a sorbitol-fermenting, Shiga-toxin-negative Escherichia coli O157:NM isolate with an atypical type III secretion system.
abstract: Reports show that sorbitol-fermenting (SF) Escherichia coli O157 isolates are implicated in animal and human diseases and may represent new emerging pathogens. We investigated the cytotoxicity and interaction with intestinal tissues of an SF, Shiga-toxin-negative E. coli O157:NM isolate. This bovine isolate was negative for stx genes and was not cytotoxic for Vero cells. We found that this E. coli O157 isolate possesses an intimin of type beta, whereas the translocated intimin receptor Tir and type III secretion system components EspA, EspB, and EspD were of type alpha. In contrast, Shiga-toxin-positive O157:H7 isolates usually possess variants of type gamma. The isolate did not present typical O157:H7 attaching and effacing lesions in the newborn pig ileal in vitro organ culture model. However, extensive effacement and elongation of the microvilli were observed. In vitro organ culture results suggest that such an SF, Shiga-toxin-negative O157:NM isolate found in cattle may potentially cause disease, such as diarrhea without hemolytic uremic syndrome, in humans.
authors.affiliation: Département de Biologie, Faculté des Sciences, Centre d'Etude et de Valorisation de la Diversité Microbienne (CEVDM), Université de Sherbrooke, Sherbrooke, Quebec, Canada.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lefebvre
authors.forename: Moussa S
authors.initials: MS
authors.lastname: Diarra
authors.forename: John M
authors.initials: JM
authors.lastname: Fairbrother
authors.forename: Eric
authors.initials: E
authors.lastname: Nadeau
authors.forename: Maurice
authors.initials: M
authors.lastname: Dubois
authors.forename: François
authors.initials: F
authors.lastname: Malouin
mesh_terms: D018829:Adhesins, Bacterial / Q000145:classification / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001422:Bacterial Adhesion; D002417:Cattle; D002522:Chlorocebus aethiops; D004927:Escherichia coli Infections / Q000378:metabolism / Q000473:pathology; D019453:Escherichia coli O157 / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D005798:Genes, Bacterial; D054884:Host-Pathogen Interactions; D007082:Ileum / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008871:Microvilli / Q000382:microbiology / Q000473:pathology; D011956:Receptors, Cell Surface / Q000145:classification / Q000378:metabolism; D012007:Rectum / Q000382:microbiology; D055571:Secretory Pathway; D022621:Shiga Toxin / Q000235:genetics / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism*; D034421:Sus scrofa; D014709:Vero Cells
chemical_list: D018829:Adhesins, Bacterial; D029968:Escherichia coli Proteins; D011956:Receptors, Cell Surface; C109287:Tir protein, E coli; C073819:eaeA protein, E coli; D013012:Sorbitol; D022621:Shiga Toxin