Olivia Freeman¹, Flavia Zendri¹, Gina Pinchbeck¹, Alan Radford¹, Ashley Ward¹, April Lawson¹, Tamsin Dewé², Shirley Bonner¹, Dorina Timofte¹

¹1Department of Veterinary Anatomy, Physiology and Pathology, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United Kingdom. ²2Veterinary Medicine Directorate, Surrey, United Kingdom

Objectives

To generate standardised antimicrobial susceptibility testing (AST) data for Escherichia coli isolates from companion animal clinical infections to improve understanding of antimicrobial resistance (AMR) patterns across the UK.

Methods

A laboratory-based cross-sectional study investigating AST profiles generated by broth microdilution assays of Escherichia coli isolates (n=450), collected from diagnostic laboratories in the UK. Tested isolates included equal proportions of 3rd-generation cephalosporin (3GCS)–susceptible and –resistant strains originating from urine (n=420) and soft tissue (n=30). Descriptive analysis was conducted in Microsoft Excel. Multidrug resistance (MDR) was defined as resistance to at least one agent in ≥3 antibiotic classes.

Results

All isolates in the study were resistant to at least one antibiotic class; MDR was identified in all canine isolates from soft tissue, and in 34.5%, 34.6% of canine and feline urine tested isolates, respectively. Among canine urine isolates analysed, within the β-lactam class, resistance was most frequently observed to aminopenicillins (32.2%), whilst 16.1% isolates demonstrated 3GCS resistance. Among feline urine isolates tested, resistance to penicillins and β-lactamase inhibitors, 1^st/2^ndGCS, and 3rd/4^thGCS was observed at similar levels (~20%). Carbapenem resistance was identified in 4 canine and 5 feline isolates. Among isolates from canine soft tissue, resistance to 4 antibiotic classes were >95%. 

Statement: Impact/ Clinical Significance

Surveillance of AMR in companion animals remains limited, with variable AST methodologies used by UK private veterinary laboratories. This standardised dataset will enable better surveillance of AMR in companion animal clinical infections supporting efforts to mitigate the public health threat posed by AMR.