mcr-1 prevalence in E. coli from healthy poultry in France
Colistin is an antibiotic that has been used for decades in veterinary medicine to control gastrointestinal infections in animals, and it is also used to treat infections in poultry. The first mobile colistin resistance gene, mcr-1, was discovered in Escherichia coli isolates of various origins, first in China and then worldwide across multiple bacterial species. Since 2015, nine new mcr genes (mcr-2 to mcr-10) and subvariants have been described in Enterobacterales. In the commensal E. coli strain collection isolated from livestock in France between 2007 and 2014, the average prevalence of mcr-1 was 5.9% in turkeys and 1.8% in broilers, indicating that mobile colistin resistance was already widespread in farm animals. The French national Ecoantibio2 plan was established in 2017 and funded by the French Ministry of Agriculture, Food, and Forestry. The objective of this plan was to reduce the use of antibiotics in veterinary medicine.
A new study, published in Frontiers in Microbiology found that in 2020, in France, the prevalence of resistance to colistin in poultry production was 3% in turkeys and 1% in broilers, showing a highly significant positive correlation with a 68% decrease in poultry exposure to colistin since 2014. More than 80% of isolates are multi-drug resistant, with 40% of isolates originating from turkeys and 44% originating from broilers co-resistant to the critically important antimicrobial ciprofloxacin. The decrease in colistin resistance among poultry in France can be considered a positive outcome of the national action plans for reduced colistin usage.
