Antimicrobial Use and Antimicrobial Resistance Indicators-Integration of Farm-Level Surveillance Data From Broiler Chickens and Turkeys in British Columbia, Canada

Abstract

Using data from the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS), we aimed to describe trends in antimicrobial use (AMU) in broiler chickens and turkeys, to compare AMU across species, to compare with trends in antimicrobial resistance (AMR), and to assess the effects of various AMU/AMR units of measurement (metrics and indicators) on data integration. Data on AMU and AMR in enteric bacteria, collected from 2013 to 2017 from broiler chickens (n = 143 flocks) and turkeys (n = 145) were used. In broiler chickens, the total AMU in milligrams/population correction unit (mg/PCU_Br) decreased by 6%, the number (n) of defined daily doses for animals using Canadian standards (nDDDvetCA) per 1,000 broiler chicken-days decreased by 12%, and nDDDvetCA/PCU decreased by 6%. In turkeys, the mg/PCU_Tk decreased by 1%, whereas the nDDDvetCA/1,000 turkey-days and the nDDDvetCA/PCU increased by 1 and 5%, respectively. The types of antimicrobial classes used in both species were similar. Using the frequency of flocks reporting use (i.e., number of flocks reporting use/number of flocks participating) as a measurement, the use of certain antimicrobials changed over time (e.g., Broilers, decreased cephalosporin use, virginiamycin use, emerging use of lincomycin-spectinomycin, and avilamycin; Turkeys: increased trimethoprim-sulfonamides and macrolide use). The trends in resistance to specific antimicrobials paralleled the frequency and quantity of use (e.g., ceftriaxone use decreased-ceftriaxone resistance decreased, and gentamicin use increased-gentamicin resistance increased) in some situations, but not others (decreased fluoroquinolone use-increased ciprofloxacin resistance). AMR data were summarized using the AMR indicator index (AMR Ix). The most notable AMR Ix trend was the decrease in ceftriaxone AMR Ix among Escherichia coli (0.19 to 0.07); indicative of the success of the poultry industry action to eliminate the preventive use of third generation cephalosporins. Other trends observed were the increase in ciprofloxacin AMR Ix among Campylobacter from 0.23 to 0.41 and gentamicin AMR Ix among E. coli from 0.11 to 0.22, suggestive of the persistence/emergence of resistance related to previous and current AMU not captured in our surveillance timeframe. These data highlight the necessity of multiple AMU and AMR indicators for monitoring the impact of stewardship activities and interventions.

Keywords: Canada; farm-level; indicators; metrics; surveillance.

Figure 1

Antimicrobial use indicators comparing broiler chickens and turkeys, 2013–2017. (A) Milligrams/population correction unit. (B) Number of defined daily doses in animals/1,000 animal-days at risk. (C) Number of defined daily doses in animals/population correction unit. Aggregated class data was comprised of 3rd generation cephalosporins, fluoroquinolones, aminoglycosides, and lincosamides-aminocyclitols.

Figure 2

Temporal variations of resistance in Escherichia coli, Salmonella, and Campylobacter in broiler chickens and turkeys, 2013–2017.

Figure 3

Multiclass resistance data in broiler chickens and turkeys, 2013–2017. (A) Escherichia coli, % of antimicrobial classes in resistance patterns. (B) Salmonella, % antimicrobial classes in resistance patterns. (C) Campylobacter, % antimicrobial classes in resistance pattern. As per routine CIPARS analysis (9, 23), the number of isolates by antimicrobial classes in the resistance pattern were grouped into 5 resistance patterns as follows: 0, 1, 2–3, 4–5, and 6–7.

Figure 4

Antimicrobial use frequency and antimicrobial resistance in Escherichia coli in broiler chickens and turkeys. (A) Percentage of flocks using ceftiofur and percentage of Escherichia coli isolates resistant to ceftriaxone. (B) Percentage of flocks using gentamicin and lincomycin-spectinomycin and percentage of Escherichia coli isolates resistant to gentamicin.

Figure 5

Milligrams/population correction unit (mg/PCU) and antimicrobial resistance indicator index (AMR Ix) for Escherichia coli in broiler chickens and turkeys. (A) Milligram/population correction unit_poultry (total use) and AMR lx (multiclass/susceptible isolates). (B) Milligram/population correction unit_poultrv (ceftiofur use) and AMR lx (ceftriaxone resistance). (C) Milligram/population correction unit_poultrv (gentamicin and lincomycin-spectinomycin use) and AMR (gentamicin resistance). AMR, antimicrobial resistance; mg/PCU_poultry, the total milligrams/population correction unit in broiler chickens and turkeys combined; AMR Ix, antimicrobial resistance indicator index; CRO-R, ceftriaxone-resistant; GEN-R, gentamicin-resistant, ≥2 Multiclass-R, sum of all isolates that exhibited resistance to 2 or more classes of antimicrobials.