Review of the pharmacodynamics of antibiotic use in animal food production.

Much attention has been focused on food-producing animals as a potential source of antimicrobial-resistant bacteria in humans. These efforts, however, have been met with continued debate and disagreement within the medical, veterinary, and regulatory communities as to whether the veterinary use of antimicrobials is a significant risk factor for the development of antimicrobial-resistant pathogens. As such, it is the purpose of our paper to assess factors involved in the pharmacokinetics and pharmacodynamics of antibiotic use in animal food production. We conclude that, based on the number of variables involved and the lack of definitive studies, it is difficult to determine the AUC:MIC for antimicrobials. Unfortunately, we are left only with general principles that indicate that low doses of antibiotic tend to select for bacterial resistance, and high doses tend to kill the microorganism. In the case where animal-associated pathogens cause human disease, those practices that target adequate exposures (AUC:MIC) of antimicrobials should continue, whereas those practices producing low exposures should be modified or halted to prevent the emergence and spread of resistant organisms. Copyright 2004 Elsevier Inc.