Phenotypic antimicrobial resistance in Escherichia coli strains on clinical and non-clinical isolates from broilers in Germany, France and United Kingdom

The increase of antimicrobial resistance is a global public health concern for humans and animals. Within the animal sector, poultry and especially broilers have increased its relevance as a meat source. Antimicrobial susceptibility testing (AST) data using microdilution (MIC) were collected from E.coli clinical isolates from Germany together with non-clinical E.coli isolates from Germany, France and United Kingdom (UK). French and UK AST data from clinical isolates were gathered as disc-diffusion diameters (DD). Data collection was performed from 2014 to 2017. Healthy broiler isolates were collected from the German Zoonosis-Monitoring program, the EU Harmonized Surveillance system (a native UK system) and ANSES database. Data on clinical isolates were collected from the German National Antibiotic Resistance (GermVet), the Scanning Surveillance of Veterinary Pathogens from APHA and RESAPATH from France. Antimicrobial panels were based on drug overlaps between both system types, i.e, clinical and non-clinical, within and between countries. Antimicrobial panel based on the comparison between these three countries showed an overlap on two antimicrobials (ampicillin and tetracycline). Both antimicrobials showed a higher resistance level in non-clinical isolates when comparing by country. The highest prevalence of isolates resistant to ampicillin was found in the UK: 62.9% (in 2015) in clinical isolates and 79.5% (in 2016) in non-clinical isolates. The highest resistance prevalence to tetracycline was found in France: 50% (in 2014) in clinical and 63.4% (in 2014) in non-clinical isolates. Data from diseased and healthy animals indicate different antimicrobial resistance levels. It was expected that a level of resistance would be higher based on clinical isolates compared to non-clinical isolates, as diseased broilers may carry bacteria resistant to regular antimicrobial