Invited Speaker Australian Society for Microbiology Annual Scientific Meeting 2023

Escherichia coli, antimicrobial resistance, virulence and One Health (94387)

Ethan R Wyrsch 1 , Bethany J Hoye 2 3 , Martina Sanderson-Smith 3 , Kimberly Maute 2 , Max L Cummins 1 , Veronica M Jarocki 1 , Monika Dolejska 4 5 6 7 , Steven P Djordjevic 1
  1. Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, NSW, Australia
  2. Faculty of Science, Medicine and Health, School of Earth, Atmospheric and Life Sciences (SEALS), University of Wollongong, Wollongong, NSW, Australia
  3. Illawarra Health and Medical Research Institute and Molecular Horizons, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
  4. Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic
  5. CEITEC VETUNI, University of Veterinary Sciences Brno, Brno, Czech Republic
  6. Department of Clinical Microbiology and Immunology, Institute of Laboratory Medicine, The University Hospital Brno, Brno, Czech Republic
  7. Department of Microbiology, Faculty of Medicine and University Hospital in Plzen, Charles University, Pilsen, Czech Republic

Escherichia coli is an important commensal and pathogen in humans and animals, causing both intestinal and extraintestinal disease. The evolution of E. coli as a pathogen relies on stable inheritance of horizontally acquired virulence/fitness factors, which occurs in a lineage-specific manner. The mechanisms underlying the acquisition and stable inheritance of antibiotic resistance and virulence traits are complex and often involve multiple mobile genetic elements (MGEs). Wildlife, particularly birds are increasingly recognised as important carriers of multiple drug resistant E. coli. In addition, closely related isolates and the MGEs these birds carry can be shared across the One health spectrum including in humans and companion animals. Here we present whole genome sequence data garnered from over 900 E. coli isolates sourced from the Australian silver gull, an urban-adapted wildlife species that is not a direct recipient of antibiotics but is a noted host of genes encoding resistance to clinically important antibiotics. Our analysis identified a remarkably diverse E. coli population in the silver gull, with potential emerging pathogens and insights into plasmid evolution. Pandemic E. coli sequence types including ST10, ST58 and ST131 were identified in sampling events more than 7 years apart as well as several emerging pathogenic lineages that have recently been described. Antibiotic selection approaches from gull samples led to the identification of predominantly multi-drug resistant E. coli, including those carrying genes encoding resistance to clinically important antibiotics. In contrast, pathogenic B2 lineage isolates were isolated without antibiotic selection, and many harboured a novel F64 virulence plasmid that warrants further investigation. Globally dominant, virulence-associated F plasmids were also readily identified across the whole collection, regardless of culture methodology. Our study demonstrates that a bystander host can accumulate multiple-drug resistance and potentially pathogenic E. coli across all major phylogroups.