Antimicrobial resistance and gene regulation in Enteroaggregative Escherichia coli from Egyptian children with diarrhoea: similarities and differences

Research output: Contribution to journalArticlepeer-review


  • Radwa Abdelwahab
  • Muhammad Yasir
  • Rita E Godfrey
  • Gabrielle S Christie
  • Sarah J Element
  • Faye Saville
  • Ehsan A Hassan
  • Entsar H Ahmed
  • Nagla H Abu-Faddan
  • Enas A Daef

Colleges, School and Institutes

External organisations

  • South Egypt Cancer Institute, Assiut University, Assiut, Egypt.
  • The Institute of Food Research; Norwich Research Park; Norwich UK
  • Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK.


Enteroaggregative Escherichia coli (EAEC) is a common diarrhoeagenic human pathogen, isolated from patients in both developing and industrialized countries, that is becoming increasingly resistant to many frontline antibiotics. In this study, we screened 50 E. coli strains from children presenting with diarrhea at the outpatients clinic of Assiut University Children's Hospital, Egypt. We show that all of these isolates were resistant to multiple classes of antibiotics and identified two as being typical EAEC strains. Using whole genome sequencing, we determined that both isolates carried, amongst others, blaCTX-M and blaTEM antibiotic resistance genes, as well as many classical EAEC virulence determinants, including the transcriptional regulator, AggR. We demonstrate that the expression of these virulence determinants is dependent on AggR, including aar, which encodes for a repressor of AggR, Aar. Since biofilm formation is the hallmark of EAEC infection, we examined the effect of Aar overexpression on both biofilm formation and AggR-dependent gene expression. We show that whilst Aar has a minimal effect on AggR-dependent transcription it is able to completely disrupt biofilm formation, suggesting that Aar affects these two processes differently. Taken together, our results suggest a model for the induction of virulence gene expression in EAEC that may explain the ubiquity of EAEC in both sick and healthy individuals.

Bibliographic note

Funding Information: This work was generously supported by a studentship from the Egyptian Ministry of Higher Education (Cultural Affairs and Missions Sector) and the Grant Office from the Medical School, Assiut University to RA, a Darwin Trust of Edinburgh PhD studentship to MY and BBSRC research grant BB/R017689/1 to DFB and SJWB. We thank MicrobesNG and Emily Jane Richardson for sequencing, genome annotation and helpful suggestions for the analysis of this data. Publisher Copyright: © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.


Original languageEnglish
Pages (from-to)57-74
Number of pages18
Issue number1
Early online date29 Dec 2020
Publication statusPublished - 2021


  • EAEC, antibiotic resistance, bacterial gene regulation, genome sequencing, virulence