title: Anaerobic conditions promote expression of Sfp fimbriae and adherence of sorbitol-fermenting enterohemorrhagic Escherichia coli O157:NM to human intestinal epithelial cells.
abstract: The sfp gene cluster, unique to sorbitol-fermenting (SF) enterohemorrhagic Escherichia coli (EHEC) O157:NM strains, encodes fimbriae that mediate mannose-resistant hemagglutination in laboratory E. coli strains but are not expressed in wild-type SF EHEC O157:NM strains under standard laboratory conditions. We investigated whether Sfp fimbriae are expressed under conditions that mimic the intestinal environment and whether they contribute to the adherence of SF EHEC O157:NM strains to human intestinal epithelial cells. The transcription of sfpA (encoding the major fimbrial subunit) was upregulated in all strains investigated, and all expressed SfpA and possessed fimbriae that reacted with an anti-SfpA antibody when the strains were grown on solid media under anaerobic conditions. Sfp expression was absent under aerobic conditions and in liquid media. Sfp upregulation under anaerobic conditions was significantly higher on blood agar and a medium simulating the colonic environment than on a medium simulating the ileal environment (P < 0.05). The induction of Sfp fimbriae in SF E. coli O157:NM strains correlates with increased adherence to Caco-2 and HCT-8 cells. Our data indicate that the expression of Sfp fimbriae in SF E. coli O157:NM strains is induced under conditions resembling those of the natural site of infection and that Sfp fimbriae may contribute to the adherence of the organisms to human intestinal epithelium.
authors: Institute of Hygiene, University of Münster, Münster, Germany.
authors: Anne
authors: A
authors: Müsken
authors: Martina
authors: M
authors: Bielaszewska
authors: Lilo
authors: L
authors: Greune
authors: Christian H
authors: CH
authors: Schweppe
authors: Johannes
authors: J
authors: Müthing
authors: Herbert
authors: H
authors: Schmidt
authors: M Alexander
authors: MA
authors: Schmidt
authors: Helge
authors: H
authors: Karch
authors: Wenlan
authors: W
authors: Zhang
mesh_terms: D000693:Anaerobiosis; D018938:Caco-2 Cells; D017931:DNA Primers / Q000235:genetics; D019453:Escherichia coli O157 / Q000378:metabolism* / Q000648:ultrastructure; D005285:Fermentation; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D006386:Hemagglutination Tests; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D008854:Microscopy, Electron; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013012:Sorbitol / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D017931:DNA Primers; D036781:Fimbriae Proteins; D013012:Sorbitol