Salmonella spp. prevalence and antimicrobial resistance in broiler chicken and turkey flocks in Canada from 2013 to 2018

Salmonella infections are a major human health concern. In the elderly and immunocompromised, infections can be life-threatening and may require antibiotic therapy. Where antibiotic therapy is required, antimicrobials of choice include fluoroquinolones and extended-spectrum cephalosporins (ESC). The aim of this study is to utilize data from the Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) to compare the prevalence of Salmonella serovars between broiler chicken and turkey flocks across Canada, and to gain an understanding of the prevalence of resistance to antimicrobials categorized as important to human health. There were 1,596 Salmonella isolates obtained from 514 broiler chicken flocks, and 659 Salmonella isolates obtained from 217 turkey flocks (2013-2018). All isolates were obtained from pooled faecal samples. Among broiler chicken flocks, the top three serovars were Kentucky (n = 573, 36%), Enteritidis (n = 314, 20%) and Heidelberg (n = 127, 8%). Resistance to ceftriaxone among Salmonella ser. Kentucky decreased from 27% in 2013 to 22% in 2018. There was no resistance among Salmonella ser. Enteritidis reported until 2018 when one isolate from British Columbia was resistant to ampicillin, streptomycin, sulphisoxazole and tetracycline. Salmonella ser. Heidelberg resistance to ceftriaxone decreased from 19% in 2013 to 14% in 2018. Among turkey flocks the top three serovars were Uganda (n = 109, 16.5%), Hadar (n = 85, 12%) and Muenchen (n = 66, 10%). No isolates of Salmonella ser. Uganda or Salmonella ser. Muenchen were resistant to any beta-lactams. Salmonella ser. Hadar (34/81, 42%) exhibited resistance to ampicillin. There was no resistance to quinolones among turkey isolates. Emerging resistance among Salmonella ser. Enteritidis, and resistance to beta-lactams and fluoroquinolones among Salmonella ser. Kentucky from broilers are cause for concern as these classes of antimicrobials are important for treatment of salmonellosis.