Reference | Mo2016 (10064)

The study was designed as a longitudinal study with each broiler flock as the study unit. The study population consisted of 62 randomly selected commercial broiler producers located in Hedmark county and affiliated to the largest broiler production company in Norway, Nortura Samvirkekylling. The random selection was generated using the command surveyselect in SAS Enterprise Guide 6.1. Criteria for inclusion in the study were as follows; active commercial broiler producer, farm located in Hedmark county, affiliation to Nortura Samvirkekylling, respond to questionnaire, and providing samples from a minimum of two broiler flocks housed at the farm during the study period. We expected a flock prevalence of 30% (p = 0.30, q = 1–0.30 = 0.70) based on previous knowledge on occurrence of cephalosporin-resistant E. coli in Norwegian broilers. When applying a 95% confidence level(Z = 1.96) and an acceptable error of 5% (L = 0.05), this resulted in a sample size of 323 flocks. We further assumed that each producer would supply samples from an average of 6.5 flocks, proposing a required inclusion of at least 62 producers, as the expected response rate was 80%. An online questionnaire was designed in order to collect information about potential risk factors for the presence of cephalosporin-resistant E. coli in broiler flocks. The questionnaire included 58 multiple choice questions on potential risk factors for occurrence of cephalosporin-resistant E. coli in the broiler flock

Broiler producers were instructed to sample broiler flocks housed at the farm from February 2014 through January 2015. Sampling was performed once during the production period using boot swabs. A flock was defined as broilers housed in a single house atthe same farm during the same time period. All sampled flocks consisted exclusively of the hybrid Ross 308

AST Method: Disk Diffusion

Reference explicitly reports AST breakpoints: False

Reference reports using a MIC table: False