Longitudinal carriage of extended-spectrum beta-lactamase producing E. coli by raw and non-raw-fed dogs, their owners and the home environment
Background: Dogs fed raw meat diets (RMD) have been demonstrated to be at increased risk of shedding antimicrobial-resistant (AMR) bacteria. However, the persistence of shedding by dogs fed RMD over an extended period, and the risks this may pose to households, has not been investigated previously. This UK-based exploratory study investigated longitudinal faecal shedding of AMR-Escherichia coli by dogs fed RMD and cooked diets, and their owners, and explored contamination of the household environment. Canine and human faecal samples, and swabs of the dog food bowl, water bowl and floor, were collected monthly between June-December 2022 alongside questionnaires discussing lifestyle factors. Samples underwent culture and antimicrobial susceptibility testing via disc diffusion using EUCAST guidelines to determine the presence of AMR-E. coli including extended-spectrum beta-lactamase (ESBL) producers. Isolates subsequently underwent whole genome sequencing. Descriptive analysis was undertaken to investigate associations with lifestyle factors and carriage of AMR-E. coli.  Results: Nineteen households participated in the study, with nine households completing the sampling period. E. coli was frequently isolated from dog and human faecal samples, but was infrequently isolated from food bowls, water bowls and floor swabs. There was evidence of shared AMR-E. coli between dogs and owners.  ESBL-producing E. coli was only isolated from faecal samples from RMD-fed dogs, and infrequently from owners. Multiple ESBL genes were identified, including emerging genes of concern blaCTX-M-55 and blaSHV-66, associated with RMD-fed dogs.  Conclusions: RMD-fed dogs may shed E. coli with important resistance mechanisms over a prolonged[GM3.1][GM3.2] time, thus feeding RMD may pose a risk of AMR transmission to households.
Background: Dogs fed raw meat diets (RMD) have been demonstrated to be at increased risk of shedding antimicrobial-resistant (AMR) bacteria. However, the persistence of shedding by dogs fed RMD over an extended period, and the risks this may pose to households, has not been investigated previously. This UK-based exploratory study investigated longitudinal faecal shedding of AMR-Escherichia coli by dogs fed RMD and cooked diets, and their owners, and explored contamination of the household environment. Canine and human faecal samples, and swabs of the dog food bowl, water bowl and floor, were collected monthly between June-December 2022 alongside questionnaires discussing lifestyle factors. Samples underwent culture and antimicrobial susceptibility testing via disc diffusion using EUCAST guidelines to determine the presence of AMR-E. coli including extended-spectrum beta-lactamase (ESBL) producers. Isolates subsequently underwent whole genome sequencing. Descriptive analysis was undertaken to investigate associations with lifestyle factors and carriage of AMR-E. coli.  Results: Nineteen households participated in the study, with nine households completing the sampling period. E. coli was frequently isolated from dog and human faecal samples, but was infrequently isolated from food bowls, water bowls and floor swabs. There was evidence of shared AMR-E. coli between dogs and owners.  ESBL-producing E. coli was only isolated from faecal samples from RMD-fed dogs, and infrequently from owners. Multiple ESBL genes were identified, including emerging genes of concern blaCTX-M-55 and blaSHV-66, associated with RMD-fed dogs.  Conclusions: RMD-fed dogs may shed E. coli with important resistance mechanisms over a prolonged[GM3.1][GM3.2] time, thus feeding RMD may pose a risk of AMR transmission to households.