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Updated: May 31, 2026
Characterization of a Pathogenic Escherichia coli Strain Derived from Oreochromis spp. Farms Using Whole-Genome Sequencing
Published on: December 23, 2022
Typing of O26 enterohaemorrhagic and enteropathogenic Escherichia coli isolated from humans and cattle with IS621
J G Mainil1, M Bardiau, T Ooka
1Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium. jg.mainil@ulg.ac.be
Aims:
This study evaluated a typing method of O26:H11 enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) based on the variation in genomic location and copy numbers of IS621.
Methods And Results:
Two multiplex PCRs, targeting either the left (5') or right (3') IS/chromosome junction of 12 IS621 insertion sites and one PCR specific of another truncated copy, were developed. Thirty-eight amplification profiles were observed amongst a collection of 69 human and bovine O26:H11 EHEC and EPEC. Seventy-one per cent of the 45 EHEC and EPEC with identical IS621 fingerprints within groups of two, three or four isolates had >85% pulsed field gel electrophoresis (PFGE) profile similarity, including four groups of epidemiologically related EHEC or EPEC, while most of the groups had <85% similarity between each others. Epidemiologically related EHEC from each of three independent outbreaks in Japan and Belgium also exhibited identical IS621 fingerprints and PFGE profiles.
Conclusions:
The IS621 fingerprinting and the PFGE are complementary typing assays of EHEC and EPEC; though, the former is less discriminatory.
Significance And Impact Of The Study:
The IS621 printing method represents a rapid (24 h) first-line surveillance and typing assay, to compare and trace back O26:H11 EHEC and EPEC during surveys in farms, multiple human cases and outbreaks.
