Evidence that faecal carriage of resistant Escherichia coli by 16-week-old dogs in the United Kingdom is associated with raw feeding and that E. coli from these dogs are shared with humans and cause opportunistic infections.

We report a survey (August 2017 to March 2018) and risk factor analysis of faecal carriage of antibacterial-resistant (ABR) Escherichia coli in 223 sixteen-week-old dogs in the United Kingdom. Raw feeding was associated with the presence of E. coli resistant to fluoroquinolones, tetracycline, amoxicillin, and streptomycin, but not to cefalexin or cefotaxime. Whole genome sequencing of 30 fluoroquinolone-resistant (FQ-R), 22 cefotaxime-resistant (CTX-R) and seven dual FQ-R/CTX-R E. coli isolates showed a wide range of sequence types (STs), an approximately 50:50 split of CTX-M:AmpC-mediated CTX-R, and almost exclusively mutational FQ-R dominated by ST744 and ST162. Comparisons between E. coli isolates from puppies known to be located within a 50 x 50 km region with those isolated from human urinary tract and bloodstream infections (isolated in parallel in the same region) identified a clone of ST963 E. coli carrying chromosomal blaCMY-2 in two puppies and causing two urinary tract infections and one bloodstream infection. Furthermore, an ST744 FQ-R clone was carried by one puppy and caused one urinary tract infection. Accordingly, we conclude that raw feeding is associated with carriage of ABR E. coli in dogs even at sixteen weeks of age and that bacteria carried by these dogs are shared with humans and cause serious opportunistic infections. We therefore suggest that those who feed their dogs raw meat seriously consider the potential ABR-transmission threat their pet may become as a result and deploy appropriate hygiene practices in mitigation.