CEI Comments regarding FDA's Draft Guidance on the Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals

CEI Comments regarding FDA's Draft Guidance on the Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals

August 30, 2010

Executive Summary

The Competitive Enterprise Institute respectfully submits these comments on the agency’s Draft Guidance on The Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals (Guidance #209).  The Competitive Enterprise Institute (CEI) is a 501(c)(3) non-profit public interest group dedicated to promoting rational risk regulation and consumer choice.  CEI has a long history of research and advocacy regarding the regulation of health and safety risks, with a particular emphasis on food and drug safety.  We have frequently observed that attempts to limit exposure to certain risks unintentionally increases exposure to other, potentially more hazardous risks. 

The development by human pathogens of resistance to medically important antimicrobials poses serious public health issues.  However, the use of such products in animals is only one factor in the emergence of antimicrobial-resistant pathogens, and it contributes far less to the development of resistance than does misuse among human patients. Most importantly, though, the use of antimicrobial drugs in food-producing animals delivers substantial benefits for both animal and human health. Even the often criticized sub-therapeutic uses of these drugs contribute to reduced pathogen loads in animal-derived foods and have a positive impact on human safety. We therefore caution the FDA and other regulatory authorities not to forbid these uses without first assessing whether such restrictions would do more harm than good.

It is unrealistic to expect that the effectiveness of any given antimicrobial can be preserved indefinitely.  But, when used judiciously in animals or humans, the development of resistance to antimicrobials may be delayed.  Eventually, however, older classes of antimicrobials that can no longer be relied upon as effective therapeutic agents will have to be replaced with newer therapeutic options, including but not limited to new classes of antimicrobial drugs.  

This does not mean, however, that society should necessarily be forced to forgo entire categories of use for the sole purpose of prolonging the effective life of any one or more antimicrobials.  A refusal to permit beneficial uses in the present can have negative impacts on human and animal health just as surely as a lack of long-term efficacy can.  Consequently, we ought to strive to achieve an optimal level of antimicrobial use of that balances the current benefits of antimicrobial consumption against the inevitable development of resistance.  In many, if not all cases, this will include the continued use of antimicrobial drugs that are important in livestock production, including sub-therapeutic uses for growth promotion.

The FDA surely recognizes that the use of antimicrobial drugs in livestock, even at sub-therapeutic doses, is important for ensuring animal health and that it delivers economic benefits to the meat, milk, and egg production industry.  However, any appropriate analysis of the propriety of continued antimicrobial drug use in livestock must also account for the tremendous benefits that human consumers derive from these applications.  Consumers benefit from the availability of a broad array of food choices at increasingly affordable prices.  But humans also derive health benefits from the presence of safer and healthier livestock animals.

The use of antimicrobial drugs in livestock results in healthier animals with fewer zoonotic infections, which in turn reduces the likelihood that these diseases will spread to humans from animals or animal-derived food products.  Recent research indicates that carcasses from slaughtered animals not treated with antimicrobials are more likely to be contaminated with human pathogenic microorganisms than those from treated animals.   Preventing the occurrence of disease in individual animals, and stopping the spread of such diseases throughout herds and flocks once they appear are important for keeping these diseases from affecting human populations.  Farmers and slaughterhouse workers who handle animals are better protected, and the meat, milk, and eggs from those animals are made safer and more healthful for consumers.  Thus, animal applications of antimicrobial drugs can have important and direct human health benefits even as inevitable pathogenic resistance is developing.

On the other hand, it remains unclear whether further restrictions on antimicrobial use in livestock would even deliver the benefit of reduced resistance. Following similar restrictions in the European Union, resistance to some antimicrobials decreased among some pathogens in various livestock animal species between 1997 and 2005, resistance among other pathogens to other antimicrobials in other animals rose.  That is, the ban on antimicrobials as growth promoters produced no consistent results.  “The expected decrease in the incidence of resistant human pathogens did not occur.  Instead, prevalence of many resistant human pathogens increased, in some cases up to 49 percent of the pre-ban incidence.”   And, while no consistent effect has been measured, the increase in use of antimicrobial drugs to treat active infections in livestock is often seen in drug classes that are more important to human medicine. 

Although the FDA and the broader public health community may be tempted to phase out or otherwise restrict the use of important antimicrobial drugs for livestock growth promotion, the experience of European countries in instituting similar restrictions should serve as a clear caution.  The effect of antimicrobial resistance on human health is a complex problem that cannot be solved by superficially appealing solutions.  Before finalizing this Guidance #209, FDA should undertake a more comprehensive analysis of the potential negative human health effects of the proposed limits on medically important antimicrobial drugs.