AVMA Member Hopeful Association Will Revisit Antimicrobial Position

Raymond J. Tarpley, D.V.M., Ph.D.
U.S. industrial animal agriculture routinely incorporates low-dose concentrations of antimicrobials into the feed or water of healthy production animals for the purposes of growth promotion and feed efficiency, an application approved by the U.S. Food and Drug Administration (FDA). This practice selects for resistance among bacteria exposed to antimicrobials, and there has been concern that such resistance could negatively impact public health. Considerable evidence is accumulating that these resistant organisms (and/or antimicrobial residues) move beyond the food animal production operation via 1. food products, 2. soils (upon which animal wastes are applied), 3. water (waste runoff into surface streams and seepage into underground aquifers), 4. crops (antimicrobial uptake from soil), 5. air (blown out of animal holding facilities by industrial tunnel fans), 6. insect carriage (e.g., flies), 7. rodent carriage and 8. human carriage (e.g., farm personnel).

During a time when bacterial resistance to an array of antimicrobials is increasing, renewed attention has been directed toward the threat that resistance arising from low-dose use of antimicrobials on food animal production farms could pose for human and veterinary pharmaceuticals, particularly with fewer novel antimicrobials reaching the market. We now know that resistance to antimicrobials can develop rapidly, extend to other antimicrobials in the same or a different class, and be shared among bacteria through multiple genetic exchange mechanisms within or between genera, culminating in multi-drug resistance in some organisms. While the FDA has recognized the threat that resistance might present, regulatory action has been slow to evolve on this problem, particularly in an atmosphere of industry pushback. Nevertheless, discontinued use of antimicrobials for non-therapeutic use has been called for by the World Health Organization, the World Organization for Animal Health, the Food and Agricultural Organization, the American Medical Association, the American Public Health Association, the American College of Preventive Medicine, the Council of State and Territorial Epidemiologists, the Infectious Diseases Society of America and others. Read More >