Abstract
We used whole-genome sequencing to investigate the evolutionary context of an emerging highly pathogenic strain of Shiga toxin–producing Escherichia coli (STEC) O157:H7 in England and Wales. A timed phylogeny of sublineage IIb revealed that the emerging clone evolved from a STEC O157:H7 stx-negative ancestor ≈10 years ago after acquisition of a bacteriophage encoding Shiga toxin (stx) 2a, which in turn had evolved from a stx2c progenitor ≈20 years ago. Infection with the stx2a clone was a significant risk factor for bloody diarrhea (OR 4.61, 95% CI 2.24–9.48; p<0.001), compared with infection with other strains within sublineage IIb. Clinical symptoms of cases infected with sublineage IIb stx2c and stx-negative clones were comparable, despite the loss of stx2c. Our analysis highlighted the highly dynamic nature of STEC O157:H7 Stx-encoding bacteriophages and revealed the evolutionary history of a highly pathogenic clone emerging within sublineage IIb, a sublineage not previously associated with severe clinical symptoms.
| Original language | English |
|---|---|
| Pages (from-to) | 2303-2308 |
| Number of pages | 6 |
| Journal | Emerging Infectious Diseases |
| Volume | 24 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Dec 2018 |
Bibliographical note
Funding Information:The research was funded by the National Institute for Health Research (NIHR) Health Protection Research Unit (in Gastrointestinal Infections at University of Liverpool in partnership with Public Health England, in collaboration with University of East Anglia, University of Oxford, and the Quadram Institute. The views expressed are those of the authors and not necessarily those of the National Health Service, the NIHR, the Department of Health, or Public Health England.
Funding Information:
We thank Florence Aromona, Lukeki Kaindama, Nalini Purohit, and Mike Harte for their contributions to the National Enhanced Surveillance System for STEC in England, and all public health practitioners who report to the system. We also thank all the laboratory staff in the Gastrointestinal Bacteria Reference Unit, especially Michela Wright, Amy Gentle, Neil Perry, and Dawn Hedges. The research was funded by the National Institute for Health Research (NIHR) Health Protection Research Unit (in Gastrointestinal Infections at University of Liverpool in partnership with Public Health England, in collaboration with University of East Anglia, University of Oxford, and the Quadram Institute. The views expressed are those of the authors and not necessarily those of the National Health Service, the NIHR, the Department of Health, or Public Health England.
Publisher Copyright:
© 2018, Centers for Disease Control and Prevention (CDC). All rights reserved.
