Antimicrobial resistance in bovine respiratory disease pathogens: measures, trends, and impact on efficacy.

The introduction of newer antimicrobial agents over the past two decades has dramatically improved the treatment of bovine respiratory disease (BRD). In the same time period, the implementation of standardized susceptibility test methods and BRD-specific interpretive criteria has substantially improved the ability to detect clinical resistance in the BRD pathogens. Although overall levels of resistance to the newer antimicrobial agents are generally low, recent data have indicated the potential for emergence and dissemination of a resistant clone in cattle. These data indicate the need for long-term surveillance of antimicrobial resistance in the BRD pathogens and a better understanding of the epidemiology of antimicrobial resistance in these pathogens.