What should healthcare providers know about antibiotics and agriculture? Here, a leading infectious diseases pharmacist discusses the topic and answers 5 key questions regarding what doctors, pharmacists, nurses and others should know about antibiotic use in agriculture.
Authored By: Emily Heil, Pharm.D., BCPS-AQ ID
1. Why are antibiotics used in agriculture in the first place?
The practice dates back to the early 1950s. Scarred by the meat shortages during the World Wars, scientists were racing to find ways to increase efficiency of animal production on farms.
Scientists at the American Cyanamid Lederle laboratory discovered that animals fed vitamin B-12 created from residues from the manufacture of the antibiotic aureomycin grew 50% faster than those who were fed vitamin B12 manufactured from other residues. After this discovery, the practice of using sub-therapeutic doses of antibiotics in animal feed for the purposes of growth promotion took off and has persisted ever since [1].
2. What is the volume of antibiotics used in agriculture?
The amount of antibiotics used in agriculture compared to human medicine is staggering. In 2014, 20 million pounds of antibiotics were sold for use in agriculture.
Of the antibiotics considered medically important by the Food and Drug Administration (FDA, Guidance for Industry #152), 97% were sold for use over-the-counter and 96% were sold in either feed or water indicating the use was for growth promotion purposes.
Antibiotics sold for food animal production account for 70% of total medically important antibiotic sales by volume [2-3].
3. Why is the use of antibiotics on the farm concerning for human health?
The antibiotics used in animal feed and water are not necessarily the exact products used in humans, but are often close analogs and therefore share the same mechanisms of resistance. Frequent use of sub-therapeutic doses of antibiotics in feed and water drives the development of antibiotic resistant organisms in animal populations.
Beyond transmission of antibiotic resistance to humans through consumption of undercooked meat, there are also multiple other mechanisms through which antibiotic resistant organisms can be transferred from food-producing animals to humans.
Resistance can spread through direct contact with farm animals to farmers and animal handlers who then have contact with the rest of society. Additionally, there are multiple environmental reservoirs for antibiotic resistance including waste water runoff from farms harboring both resistant bacteria and therapeutic levels of antibiotics, manure and slurry used for crops and soil and through direct inoculation of flies, birds and other vectors that can carry resistant bacteria outside of the farm [4].
4. What’s being done legislatively to help with this problem?
The FDA has introduced two policies to phase out antibiotics for growth promotion, both of which will be fully implemented by January 1, 2017.
FDA Guidance #213 recommends the removal of growth promotion from antibiotic product labels, which would then make the use of the drugs illegal for growth promotion purposes [5]. Although this guidance is voluntary, all affected companies indicated they intend to comply.
The Veterinary Feed Directive (VFD) rule is being rolled out with Guidance #213 and outlines a process to ensure veterinary oversight of drugs available for use in animal feed which will effectively keep the use of medically important antibiotics from being used over-the-counter without veterinary oversight. Additionally, the VFD establishes requirements for a valid veterinarian-client-patient relationship [6].
These landmark policies will help to address some of the problems highlighted by the alarming statistics in #2, but more work is still needed.
5. What can you do?
Healthcare providers play a key role in educating the public about the growing problem of antibiotic resistance and how antibiotic use in agriculture is contributing to the problem.
Additionally, you can be an informed consumer and purchase only meat raised without antibiotics and support businesses with responsible antibiotic policies and sourcing practices.
For more information and advice on how to advocate for the cause, please visit www.saveantibiotics.org.
REFERENCES
- Ogle M. In Meat we Trust, 1st ed. Houghton Mifflin Harcourt; 2013.
- Hollis A, Ahmed Z. Preserving antibiotics rationally. NEJM. 2013;26:2474-6.
- U. S. Food and Drug Administration Summary report on antimicrobials sold or distributed for use in food-producing animals. 2014. Available at: http://www.fda.gov/animalveterinary/newsevents/cvmupdates/ucm776256.htm. (accessed 7/6/16)
- Aitken SL, Dilworth TJ, Heil EL, Nailor MD. Agricultural applications for antimicrobials. A danger to human health: An official position statement of the Society of infectious Diseases Pharmacists. Pharmacotherapy. 2016;36:422-32.
- U. S. Food and Drug Administration Guidance for Industry #213. Available at: www.fda.gov/downloads/animalveterinary/guidancecomplianceenforcement/guidanceforindustry/ucm299624.pdf. (accessed 7/6/16)
- U. S. Food and Drug Administration Veterinary Feed Directive. Available at: https://www.federalregister.gov/articles/2015/06/03/2015-13393/veterinary-feed-directive. (accessed 7/6/16)
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