Population Genetics and Antimicrobial Susceptibility of Canine Campylobacter Isolates Collected before and after a Raw Feeding Experiment

PLoS One. 2015 Jul 14;10(7):e0132660. doi: 10.1371/journal.pone.0132660. eCollection 2015.

Abstract

In recent years, increasing numbers of consumers have become interested in feeding raw food for their pet dogs as opposed to commercial dry food, in the belief of health advantages. However, raw meat and internal organs, possibly contaminated by pathogens such as Campylobacter spp., may pose a risk of transmission of zoonoses to the pet owners. Campylobacter jejuni is the leading cause of bacterial gastroenteritis in humans but C. upsaliensis has also been associated with human disease. In this study we investigated the effect of different feeding strategies on the prevalence of Campylobacter spp. in Finnish dogs. We further characterized the isolates using multilocus sequence typing (MLST), whole-genome (wg) MLST and antimicrobial susceptibility testing. Dogs were sampled before and after a feeding period consisting of commercial raw feed or dry pellet feed. Altogether 56% (20/36) of the dogs yielded at least one Campylobacter-positive fecal sample. C. upsaliensis was the major species detected from 39% of the dogs before and 30% after the feeding period. Two C. jejuni isolates were recovered, both from raw-fed dogs after the dietary regimen. The isolates represented the same genotype (ST-1326), suggesting a common infection source. However, no statistically significant correlation was found between the feeding strategies and Campylobacter spp. carriage. The global genealogy of MLST types of dog and human C. upsaliensis isolates revealed weakly clonal population structure as most STs were widely dispersed. Major antimicrobial resistance among C. upsaliensis isolates was against streptomycin (STR MIC > 4 mg/l). Apart from that, all isolates were highly susceptible against the antimicrobials tested. Mutations were found in the genes rpsL or rpsL and rsmG in streptomycin resistant isolates. In conclusion, increasing trend to feed dogs with raw meat warrants more studies to evaluate the risk associated with raw feeding of pets in transmission of zoonoses to humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed / adverse effects*
  • Animal Feed / microbiology*
  • Animals
  • Campylobacter / drug effects*
  • Campylobacter / genetics*
  • Campylobacter / isolation & purification
  • Campylobacter Infections / microbiology
  • Campylobacter Infections / transmission
  • Campylobacter Infections / veterinary*
  • Campylobacter jejuni / drug effects
  • Campylobacter jejuni / genetics
  • Campylobacter jejuni / isolation & purification
  • Campylobacter upsaliensis / drug effects
  • Campylobacter upsaliensis / genetics
  • Campylobacter upsaliensis / isolation & purification
  • Dog Diseases / microbiology*
  • Dog Diseases / transmission
  • Dogs / microbiology*
  • Drug Resistance, Bacterial / genetics
  • Finland
  • Food Microbiology*
  • Genes, Bacterial
  • Genetics, Population
  • Genotype
  • Humans
  • Microbial Sensitivity Tests
  • Multilocus Sequence Typing
  • Mutation
  • Risk Factors
  • Zoonoses / microbiology
  • Zoonoses / transmission

Grant support

SO received funding from the Finnish Foundation of Veterinary Research (no specific grant number) for conducting this study. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.