A Representative Collection of Commensal Extended-Spectrum- and AmpC-β-Lactamase-Producing Escherichia coli of Animal Origin for Phage Sensitivity Studies.

INTRODUCTION

Extended-spectrum β-lactamase (ESBL)- and AmpC β-lactamase (AmpC)-producing Escherichia coli from livestock and meat represent a zoonotic risk and biocontrol solutions are needed to prevent transmission to humans.

METHODS

In this study, we established a representative collection of animal-origin ESBL/AmpC E. coli as target to test the antimicrobial potential of bacteriophages.

RESULTS

Bioinformatic analysis of whole-genome sequence data of 198 ESBL/AmpC E. coli from pigs, broilers, and broiler meat identified strains belonging to all known E. coli phylogroups and 65 multilocus sequence types. Various ESBL/AmpC genes and plasmid types were detected with expected source-specific patterns. Plaque assay using 15 phages previously isolated using the E. coli reference collection demonstrated that Warwickvirus phages showed the broadest host range, killing up to 26 strains.

CONCLUSIONS

154/198 strains were resistant to infection by all phages tested, suggesting a need for isolating phages specific for ESBL/AmpC E. coli. The strain collection described in this study is a useful resource fulfilling such need.