The aim of this study was to describe and compare the occurrence of quinolone resistant Escherichia coli (QREC) in various animal species in relation to human population density. Data from the Norwegian monitoring programme for antimicrobial resistance in feed, food and animals from 2006 to 2016 was compiled and analysed. In total, 4568 E. coli isolates were included in this study. The isolates originated from broilers, layers, cattle, turkeys, dogs, wild birds, red foxes, reindeer, sheep, horses and pigs. Data regarding the geographical location of sampling was obtained for 4050 of these isolates and used to categorize the isolates depending on the human population density of the area. In total, 1.4% of the isolates were categorized as quinolone resistant. Compared to most European countries, there was an overall low occurrence of QREC in various animal species in Norway, though with an interspecies variation with the highest occurrence in broilers and wild birds (p < 0.05). Human population density was not associated with the occurrence of QREC. Since fluoroquinolones are not used prophylactically and in almost negligent amounts in various species in Norway, the interspecies variation in the occurrence of QREC suggests that other factors than fluoroquinolone use may be important in the development of QREC.

• Quantitative data - Quantitative data were used during the intervention

NORM-VET annual reports: NORM/NORM-VET, 2016. Usage of Antimicrobial Agents and Occurrence of Antimicrobial Resistance in Norway. Norwegian Veterinary Institute/University Hospital of North Norway, Tromsø/Oslo ISSN:1502-2307 (print)/1890-9965 (electronic).

• Animal - All activities regarding living animals

• Livestock - Places were terrestrial animals are farmed including farms, fields, orchards, pastures
• Wild animals - Animals that have not been domesticated or tamed and living in a natural environment
• Pets - Animals kept for a person's company, protection, or entertainment