Antimicrobial resistance ofEscherichia coliandEnterococcus faecalisin housed laying-hen flocks in Europe

Abstract

SUMMARYThe aim of this study was to determine the potential association between housing type and multiple drug resistance (MDR) inEscherichia coliandEnterococcus faecalisisolates recovered from 283 laying-hen flocks. In each flock, a cloacal swab from four hens was collected and produced 1102E. coliand 792E. faecalisisolates. Broth microdilution was used to test susceptibility to antimicrobials. Country and housing type interacted differently with the MDR levels of both species. In theE. colimodel, housing in a raised-floor system was associated with an increased risk of MDR compared to the conventional battery system [odds ratio (OR) 2·12, 95% confidence interval (CI) 1·13–3·97)]. In theE. faecalismodel the MDR levels were lower in free-range systems than in conventional battery cages (OR 0·51, 95% CI 0·27–0·94). In Belgium, ceftiofur-resistantE. coliisolates were more numerous than in the other countries.