Seven phylogroup A CTX-M-15-producing Escherichia coli isolates recovered from clinical and meat samples were further characterised. All of them belonged to sequence type ST410. Only 2 of the 22 virulence genes investigated were detected. All isolates carried the fimH gene encoding type 1 fimbriae, and five isolates harboured the iucD gene encoding aerobactin siderophore. A group of five isolates showed 81.2% similarity by pulsed-field gel electrophoresis (PFGE), comprising three clinical isolates belonging to ONT:H9 and two food isolates belonging to O55:H9. Different HpaI digestion patterns were observed for plasmids, but all of them belonged to IncFIB group and harboured bla CTX-M-15 associated with blaOXA-1, blaTEM, tetA, catB3 and aac(6′)-Ib surrounded by an identical genetic environment. These findings showed the possibility of lateral gene transfer of bla CTX-M-15 as well as other antibiotic resistance determinants between low-virulence food and clinical isolates.
All Science Journal Classification (ASJC) codes
- Microbiology (medical)
- Infectious Diseases
- Pharmacology (medical)