Volume 27, Number 9—September 2021
Research
Reduction in Antimicrobial Use and Resistance to Salmonella, Campylobacter, and Escherichia coli in Broiler Chickens, Canada, 2013–2019
Table 3
Incidence rate ratio of Campylobacter nC from LASSO-penalized generalized mixed-effects Poisson model in a study of antimicrobial use and in broiler chickens, Canada, 2013–2019*
Variable | Incidence rate ratio | 2.50% CI | 97.50% CI | p value |
---|---|---|---|---|
Intercept |
0.277081 |
0.1054967 |
0.7277371 |
0.00919† |
Production system (referent comparison factor: conventional) | ||||
Antimicrobial-free‡ |
0.60892 |
0.2994255 |
1.2383169 |
0.17076 |
Ideal disinfection method (referent comparison factor: no use of ideal method) | ||||
Use of ideal disinfection |
1.3043882 |
0.7766548 |
2.190714 |
0.31513 |
Continuous variable of antimicrobial use (mg/kg) | ||||
Injections (in ovo or subcutaneous§) | 1.7448076 | 0.1650191 | 18.4484971 | 0.64363 |
Through feed | 0.9979396 | 0.9923108 | 1.0036003 | 0.4748 |
Through water |
0.996652 |
0.9806929 |
1.0128707 |
0.68386 |
Sample collection year (referent comparison year: 2013) | ||||
2014 | 0.7218903 | 0.3138241 | 1.6605658 | 0.44323 |
2015 | 1.7590844 | 0.8024374 | 3.8562237 | 0.15843 |
2016 | 0.3714697 | 0.1493034 | 0.9242233 | 0.03322† |
2017 | 0.8334422 | 0.3732234 | 1.8611531 | 0.65669 |
2018 | 0.5029853 | 0.2104181 | 1.2023406 | 0.12221 |
2019 |
0.6468213 |
0.2868202 |
1.4586765 |
0.29368 |
Province (referent comparison province: Alberta) | ||||
British Columbia | 1.6638783 | 0.9144055 | 3.0276404 | 0.09551 |
Ontario | 1.5284206 | 0.7983312 | 2.9261911 | 0.20045 |
Québec | 2.0744067 | 0.9336274 | 4.6090798 | 0.07323 |
Saskatchewan | 1.8708334 | 0.5308387 | 6.5933731 | 0.32975 |
*nC, number of antimicrobial classes to which each isolate was resistant. †Statistically significant (p<0.05). ‡Antimicrobial-free flocks were not exposed to medically important antimicrobials through any route of administration. §Subcutaneous route in young chicks at the hatchery.