AUTHOR=Morgan Genever , Pinchbeck Gina , Haldenby Sam , Schmidt Vanessa , Williams Nicola 

TITLE=Raw meat diets are a major risk factor for carriage of third-generation cephalosporin-resistant and multidrug-resistant E. coli by dogs in the UK

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1460143

DOI=10.3389/fmicb.2024.1460143

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>Raw-meat diets (RMD) for dogs, comprising unprocessed or non-heat-treated animal material, are increasingly popular. However, RMDs have been demonstrated to be contaminated with antimicrobial resistant (AMR) bacteria, and there is concern that such diets may pose a zoonotic disease risk. Additionally, dogs fed RMD may shed more AMR- fecal bacteria compared to those fed conventional cooked diets. Data from the UK remain limited; the present study investigated the presence of AMR-<italic>Escherichia coli</italic> in the feces of RMD and non-RMD (NRMD)-fed dogs in the UK, the <italic>E. coli</italic> AMR gene complement, and the lifestyle risk factors associated with AMR- <italic>E. coli</italic> carriage.</p></sec><sec><title>Methods</title><p>Fecal samples from UK-owned dogs (<italic>N</italic> = 193 RMD, <italic>N</italic> = 239 NRMD) and questionnaires discussing lifestyle factors, were obtained between October 2020-August 2021. Samples underwent culture and antimicrobial susceptibility testing to determine the presence of AMR-<italic>E. coli</italic>. Whole genome sequencing determined AMR gene carriage. Risk factors for the presence of AMR-<italic>E. coli</italic> were determined by multivariable modeling.</p></sec><sec><title>Results</title><p>RMD dogs carried significantly more fecal AMR <italic>E. coli</italic> (<italic>p</italic> &lt; 0.001), including third-generation cephalosporin resistant, extended-spectrum beta-lactamase (ESBL) producing, and multidrug resistant isolates and multivariable modeling confirmed raw-meat diets to be a significant risk factor. The <italic>bla</italic><sub>CTX–M–15</sub> gene was the most frequently identified <italic>bla</italic><sub>ESBL</sub> gene. The <italic>bla</italic><sub>CTX–M–55</sub> and <italic>bla</italic><sub>SHV–66</sub> genes were also prevalent and were only found in RMD dogs. The mobile colistin resistance gene, <italic>mcr-4</italic> was identified in one ESBL-producing <italic>E. coli</italic> isolate from a NRMD-fed dog.</p></sec><sec><title>Conclusion</title><p>This study has shown that dogs fed RMD in the UK are significantly more likely to shed <italic>E. coli</italic> which is resistant to highest priority critically important antibiotics, and multidrug resistant <italic>E. coli</italic>, than dogs fed NRMD. Additionally, AMR-<italic>E. coli</italic> isolates from RMD-fed dogs harbor multiple, diverse, and novel AMR genes. Therefore, provision of RMD to dogs could pose an important potential threat to human and animal health, especially given the close nature of the relationship many owners share with their pets. Awareness of these findings should be shared with pet owners, veterinary and medical professionals, pet food manufacturers and public health to mitigate potential risks.</p></sec>