John Balbus, MD, Environmental Health, Environmental Defense, 1875 Connecticut Ave., NW, Suite 600, Washington, DC 20009, 202-387-3500, jbalbus@environmentaldefense.org

The U.S. Centers for Disease Control has identified antibiotic resistance as one of its “top concerns.” Resistance is spurred by overuse of antibiotics in agriculture as well as in human medicine, and minimizing use of antibiotics in both sectors is a vital component in slowing development of resistance. One potential area for reducing antimicrobial use is curtailing the use of antimicrobials feed additives in livestock and poultry production. Such additives, which account for an estimated 70% of the antimicrobials used in the U.S. each year, are used for “nontherapeutic” purposes, i.e., for routine prophylaxis and growth promotion rather than treatment of sick animals. About half of these drugs belong to classes of antimicrobials also used in human medicine.

This paper will examine several recent quantitative risk assessments on the health risks of antimicrobial feed additives, including the extent to which they adequately evaluate risks arising from (i) foodborne pathways, (ii) non-food pathways (i.e., workers and the environment) by which resistance genes also spread, and (iii) the ability of bacteria to share resistance genes with unrelated bacteria. The paper will also examine the Food and Drug Administration’s new Guidance for qualitatively evaluating risks of antimicrobial use in food animals, and other risk-management proposals now being discussed.

Learning Objectives:

• Describe current patterns of antibiotic use in agriculture;
• Identify three pathways by which resistant bacteria arising from agricultural use of antibiotics can reach humans;
• Analyze the extent to which quantitative risk assessment methods can, and cannot, adequately characterize the health risk associated with agricultural use of medically important antibiotics; and
• Evaluate the feasbility of alternative risk-management approaches.

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.