Association between ceftiofur use and isolation of Escherichia coli with reduced susceptibility to ceftriaxone from fecal samples of dairy cows

Abstract

Our observation of a herd-level but not an individual cow-level association between ceftiofur use and isolation of E coli with reduced ceftriaxone susceptibility from fecal samples suggests that interventions to reduce the spread of antimicrobial resistance genes in agricultural animals will be most effective at the herd level.