Exploring the relationships between antimicrobial use and resistance in Canadian turkey flocks

In a study published in Frontiers in Microbiology, researchers have modelled how antimicrobial use impacts the emergence of antimicrobial resistance (AMR) in Escherichia coli isolated from Canadian turkey flocks. The findings will help inform antimicrobial stewardship in the turkey sector.

Csaba Varga, assistant professor of epidemiology at University of Illinois Urbana-Champaign, and his research group used data that had been collected by the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS). From 2016-2019 veterinarians across Canada visited turkey farms annually to collect data on antimicrobial use and obtain faecal samples from flocks that were chosen at random.

The researchers used E. coli as an indicator of AMR; isolates from the faecal samples were tested for their susceptibility to 14 different antimicrobials.

To study the association between antimicrobial use and resistance, the researchers employed modelling techniques that considered the disease indications for antimicrobial use, the quantity of antimicrobials used, the length of treatment, the weight of birds, and the administration route.

Analysis indicated that AMR emerged with the use of related antimicrobials (e.g., tetracycline use-tetracycline resistance), however, the use of unrelated antimicrobial classes was also impacting AMR (e.g., aminoglycosides/streptogramins use-tetracycline resistance).

“Our study shows that the use of antimicrobials in the feed is the main driver of resistance,” Varga said. “In addition, antimicrobials were also injected into the eggs at the hatchery, which produced resistance in E. coli.” The researchers also found that treating certain diseases (enteric, late-stage septicemic conditions, and colibacillosis) contributed to the development of resistance to antimicrobials.

The highest variances were at the flock level, indicating that stewardship actions should focus on flock-level infection prevention practices.

The work was funded by the CIPARS Farm Surveillance, Saskatchewan Agriculture, the Ontario Ministry of Agriculture, Food and Rural Affairs, the Canadian Poultry Research Council, Alberta Agriculture and Forestry, and the Department of Pathobiology at the University of Illinois Urbana-Champaign.

Article: Shrestha, R. D., Agunos, A., Gow, S. P., Deckert, A. E., Varga, C. (2022). Associations between antimicrobial resistance in fecal Escherichia coli isolates and antimicrobial use in Canadian turkey flocks. Frontiers in Microbiology, 13, 954123, doi: 10.3389/fmicb.2022.954123

[SOURCE: University of Illinois Urbana-Champaign]