Oxygen and contact with human intestinal epithelium independently stimulate virulence gene expression in enteroaggregative Escherichia coli

Research output: Contribution to journalArticle

Authors

Colleges, School and Institutes

External organisations

  • Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UA, UK.
  • Institute of Microbiology and Infection, College of Medical and Dental Science, University of Birmingham, Birmingham, UK.

Abstract

Enteroaggregative Escherichia coli (EAEC) are important intestinal pathogens causing acute and persistent diarrhoeal illness worldwide. Although many putative EAEC virulence factors have been identified, their association with pathogenesis remains unclear. As environmental cues can modulate bacterial virulence, we investigated the effect of oxygen and human intestinal epithelium on EAEC virulence gene expression to determine the involvement of respective gene products in intestinal colonisation and pathogenesis. Using in vitro organ culture of human intestinal biopsies, we established the colonic epithelium as the major colonisation site of EAEC strains 042 and 17-2. We subsequently optimised a vertical diffusion chamber system with polarised T84 colon carcinoma cells for EAEC infection and showed that oxygen induced expression of the global regulator AggR, aggregative adherence fimbriae, E. coli common pilus, EAST-1 toxin, and dispersin in EAEC strain 042 but not in 17-2. Furthermore, the presence of T84 epithelia stimulated additional expression of the mucinase Pic and the toxins HlyE and Pet. This induction was dependent on physical host cell contact and did not require AggR. Overall, these findings suggest that EAEC virulence in the human gut is modulated by environmental signals including oxygen and the intestinal epithelium.

Bibliographic note

© 2019 The Authors Cellular Microbiology Published by John Wiley & Sons Ltd.

Details

Original languageEnglish
Article numbere13012
Number of pages12
JournalCellular Microbiology
Volume21
Issue number6
Early online date23 Jan 2019
Publication statusPublished - Jun 2019

Keywords

  • adherence, colonic epithelium, diarrhoea, EAEC, gene expression, oxygen, virulence