Scientific Opinion on Carbapenem resistance in food animal ecosystems
Carbapenems are broad-spectrum β-lactam antimicrobials used for the treatment of serious infections in humans. To date only sporadic studies have reported the occurrence of carbapenemase-producing (CP) bacteria in food-producing animals and their environment. The bacteria and enzymes isolated include VIM-1 producing Escherichia coli and Salmonella Infantis from pigs and poultry in Germany, OXA-23-producing Acinetobacter spp. from cattle and horses in France and Belgium, and NDM-producing Acinetobacter spp. from pigs and poultry in China. In the German S. Infantis and E. coli isolates, the VIM-1-encoding genes were located on IncHI2 plasmids. A methodology including selective culture is proposed for the detection of CP strains of Enterobacteriaceae and Acinetobacter spp. The choice of selective media for the surveillance of carbapenem resistance for testing animal and food samples needs to be experimentally evaluated and validated. Biochemical and phenotypic tests for the confirmatory identification of CP bacteria are available. For CP bacteria in animals and food, active/passive monitoring and/or targeted surveys should cover key zoonotic agents, animal pathogens and indicator organisms. Priority should be given to broilers, fattening turkeys, fattening pigs, veal calves and meat thereof. Because there are no data on the comparative efficacy of individual control options, prioritisation is complex. Continued prohibition of the use of carbapenems in food-producing animals would be a simple and effective option. As genes encoding carbapenemase production are mostly plasmid-mediated, and co-resistance may be an important issue in the spread of such resistance mechanisms, decreasing the frequency of use of antimicrobials in animal production in the EU in accordance with prudent use guidelines is also of high priority. The effectiveness of any control measures should be monitored by targeted surveys, using selective isolation methods and pre-enrichment of samples. Control measures should be proactively implemented at national and international levels to prevent CP strains become widespread in livestock.