Phenotypic zinc resistance does not correlate with antimicrobial multi-resistance in fecal isolates of piglets.

Background: Following the ban on antimicrobial usage for growth promotion in animal husbandry in the EU, non-antimicrobial agents including heavy metal ions (e.g. zinc and copper), prebiotics or probiotics have been suggested as alternatives.

High dietary zinc feeding promotes persistence of multi-resistant E. coli in the swine gut.

High levels of zinc oxide are used frequently as feed additive in pigs to improve gut health and growth performance and are still suggested as an alternative to antimicrobial growth promoters. However, we have recently described an increase of multi-resistant E. coli in association to zinc feeding in piglets.