Characterization of antibiotic determinants and heavy metal resistance genes in Escherichia coli from pigs in Catalonia

The study reveals that pigs are exposed to more antibiotics than humans, leading to antimicrobial resistance (AMR) among commensal and pathogenic bacteria. Heavy metals are used as feed additives, and increased exposure to copper, zinc, and cadmium can further encourage AMR. The most common AMR genes were mdfA, aph(3″)-Ib, bla TEM-1B, and aph(6)-Id. HM tolerance genes were present in almost every genome but were rarely located on the same plasmids. The exclusive association between mcr-4 and ColE10 plasmid may help target interventions to curtail AMR.