A cross-sectional study of the prevalence factors associated with fluoroquinolone resistant Campylobacter jejuni in broiler flocks in Canada.

Campylobacter infections in humans are usually self-limiting; however, antibiotic intervention may be necessary in the case of severe infection. Fluoroquinolones are often the drug of choice for treatment of campylobacteriosis; however, resistance to these drugs can develop rapidly, complicating treatment protocols. Increasing resistance to fluoroquinolones in human infections has coincided with approval of use of fluoroquinolones in animals, therefore, isolation of fluoroquinolone resistant (FQr) Campylobacter in broiler flocks is concerning. This cross-sectional study utilized data collected from 2013-2018 by the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) on-farm surveillance program to investigate prevalence factors associated with the isolation of FQr C. jejuni from broiler faecal samples. Mixed effects logistic regression models accounting for clustering of flocks within hatcheries, with and without a fixed effect for the presence of flock level tetracycline resistance were used to assess prevalence factors among 536 C. jejuni isolates from 158 flocks. Both models indicated that the type of bird used (Ross versus Cobb or mixed), the use of virginiamycin as a feed additive, the use of traps to control rodent populations in the barn, and the total number of birds in the barn were significant prevalence factors for increased FQr C. jejuni in a flock. In the model where flock level tetracycline resistance was included as a fixed effect, the odds of FQr C. jejuni increased by 16 (95% CI: 3.74, 68), and the magnitude of the effect of each of the identified prevalence factors was larger. Both models indicated that methods of disinfection of water lines between production cycles is important, with the use of chlorine being protective in the model where tetracycline resistance was included as a fixed effect, and the use of hydrogen peroxide being a risk factor in the model where tetracycline resistance was not included as a fixed effect. The use of hot water to wash the barn between production cycles was also a significant protective factor in the model where tetracycline resistance was not included as a fixed effect. These results indicate that biosecurity and sanitation procedures play a role in the dissemination of FQr C. jejuni in broiler flocks. Future analysis should seek to understand the effect of different disinfectant products on the isolation of FQr C. jejuni. Gaining a better understanding of the management of these critical practices may allow for the reduction of this enteric pathogen in broiler flocks in Canada.