Zinc and copper in animal feed – development of resistance and co-resistance to antimicrobial agents in bacteria of animal origin

摘要

Farmed animals such as pig and poultry receive additional Zn and Cu in their diets due to supplementingelements in compound feed as well as medical remedies. Enteral bacteria in farmed animals are shown todevelop resistance to trace elements such as Zn and Cu. Resistance to Zn is often linked with resistanceto methicillin in staphylococci, and Zn supplementation to animal feed may increase the proportion of multi-resistant E. coli in the gut. Resistance to Cu in bacteria, in particular enterococci, is often associated withresistance to antimicrobial drugs like macrolides and glycopeptides (e.g. vancomycin). Such resistant bacteriamay be transferred from the food-producing animals to humans (farmers, veterinarians, and consumers). Dataon dose-response relation for Zn/Cu exposure and resistance are lacking; however, it seems more likely that aresistance-driven effect occurs at high trace element exposure than at more basal exposure levels. There is alsolackofdatawhichcoulddemonstratewhetherZn/Cu-resistantbacteriamayacquireantibioticresistancegenes/become antibiotics resistant, or if antibiotics-resistant bacteria are more capable to become Zn/Cu resistantthan antibiotics-susceptible bacteria. Further research is needed to elucidate the link between Zn/Cu andantibiotic resistance in bacteria.