The emotional rhetoric surrounding this issue has resulted in knee-jerk legislative proposals to ban certain uses of antibiotics. Blunt policy instruments could be harmful when dealing with such a critical and complicated issue. It is easy to point fingers and suggest that eliminating some uses in animals would reduce antibiotic resistance in humans. But it is important to act on specific, data-driven evidence. Simple widespread bans on certain uses — including those in animals — would be detrimental to animal health and, more importantly, human health.

If we are to contain the spread of antibiotic resistance, we need careful, data-driven understanding of the sources and causes of that spread. Antibiotic resistance is a collection of specific problems, or specific pathogens resistant to particular drugs. Specific bacterial/drug combinations, or “bug-drug combos,” must be considered separately from other combinations.

Consider the top three bacterial/drug combinations identified by the Infectious Diseases Society of America as the biggest challenges facing doctors: MRSA, Acinetobacter baumannii and vancomycin-resistant enterococcus.

MRSA (methicillin-resistant staphylococcus infections) are infections that are primarily the result of treatment in hospitals, but have recently been found in community settings like schools and athletic facilities. They are the result of human-to-human transmission or contact with contaminated materials. These infections are not foodborne nor are they acquired by eating meat.

Acinetobacter baumannii is an opportunistic pathogen. High rates of infection are often found in soldiers wounded in Iraq. This pathogen is most often associated with wound infections in hospitals and other medical facilities. It is inherently resistant to many antibiotics, and has no connection to food animals or antibiotic use in food animals.

Finally, vancomycin-resistant enterococcus (VRE) is also known mostly as a hospital infection that has developed resistance because of extensive use of vancomycin in hospitals. This and other drugs in its class have never been approved for use in food animals in the United States. 

Scientific risk assessments conducted by the U.S. Food and Drug Administration or by private researchers demonstrate that none of these three bacterial/drug combinations are related to the use of antibiotics in animals.

Risk assessments allow researchers to measure each step in a chain of events to determine if the use of antibiotics in food animals harms human health. These steps include determining if the use of antibiotics in an animal will result in development of a resistant strain of bacteria; if the resistant bacteria can survive through processing and handling, or through food preparation; if a large enough dose of the bacteria can survive to cause illness in humans; and if the proposed treatments for medicating a person ill from bacterial infection would actually work.

All risk assessments conducted on the antibiotics most commonly used in animal agriculture have found that the risk to human health posed by antibiotic use in animals is extremely small. In one study in which I participated, this risk was determined to be much less than the risk of dying from a bee sting.

Legislated bans frequently result in unintended consequences. In Denmark, such a ban resulted in more animal disease and death, and the need to use more antibiotics for the treatment of disease. While the level of resistant bacteria in animals has declined, there is little evidence that resistance bacteria in humans has declined. In fact, in some cases, it has risen.

Published literature has also demonstrated that antibiotics can play a contributing role in meat safety. These studies show the relationship between the health of animals entering the food supply and the safety of the meat produced. Animal disease can increase the amount of contamination on the meat, and the use of antibiotics to keep these animals healthy helps reduce development of these pathogens.

Human health is linked to animal health in a number of ways and the careful use of antibiotics to keep food animals healthy is an important tool in ensuring greater public health. Policy decisions about the use of antibiotics must be made on the basis of careful, data-driven science, rather than on emotion.

In this context the recent FDA draft guidance, “The Judicious Use of Medically Important Antimicrobial Drugs in Food-Producing Animals,” makes some welcomed points. As the FDA suggests, the continued availability of effective antimicrobial drugs is critically important for combating infectious disease in both humans and animals. This wisdom is fundamental to any decisions made including the continued availability of such drugs for feed and water to manage disease in animals. In the interest of both human and animal health, we must take a more proactive approach to considering how antimicrobial drugs are used, and take steps to assure that such uses are appropriate and necessary for maintaining the health of humans and animals.

Peter Silley, Ph.D., is managing director of MB Consult, Ltd. and professor of applied microbiology at the University of Bradford, U.K.