Beef Raised Without the Routine Use of Antibiotics
Whoever thought that eating a steak or hamburger would actually affect the way your body responds to certain medicines? Feeding antibiotics to animals, a common practice in livestock production, is a growing public health concern because it decreases the effectiveness of antibiotics used to treat diseases in humans.
Defining “Antibiotic Resistance”
Antibiotics are drugs such as penicillin, amoxicillin and tetracycline that are used to kill or inhibit the growth of harmful bacteria. The landmark discovery of penicillin in the 1940s introduced an effective way to treat common infections and diseases and changed the way medicine is practiced today.
However, when antibiotics are used too frequently, the harmful bacteria become resistant to the drug and the treatment becomes less effective. In fact, bacteria can develop into a completely different strain that cannot be killed by the “old” antibiotic.
Antibiotics in Livestock
In 1950, scientists discovered that low doses of antibiotics make chickens grow faster than normal (1). Since then, the practice of mixing antibiotics (up to a dozen different types) in animal feed has become quite common, and scientists estimate that 70 percent of all antibiotics consumed in the United States are used for livestock production (see graph) (2).
It’s important to note that these low dose antibiotics added to feed are not necessarily used to treat diseases or infections. Over 90 percent of the antibiotics used in livestock production are for “non-therapeutic” purposes, merely to enhance growth and weight gain in the animals (3).
The overuse of non-therapeutic antibiotics in beef cattle, swine and poultry production poses a serious threat to human health. Because half of these antibiotics belong to classes of drugs used in human medicine, the risk of antibiotic resistance in humans is increased. This is especially threatening for people with compromised immune systems including infants, elderly people and patients with cancer receiving chemotherapy.
Antibiotic-resistance in humans is a tremendous public health threat worldwide. The World Health Organization held a conference on this “crisis” and concluded that there is sufficient evidence showing that “the major transmission pathway for resistant bacteria…[is] from food animals to humans” and that this has led to “increased frequency of treatment failures (in some cases death) and increased severity of infections” (4). In their recommendations, the WHO specifically called for stricter legislation to minimize antimicrobial usage in agriculture because it is so prevalent and may pose a significant risk to human health (5).
Antibiotic-resistant bacteria can be transmitted from animals to humans in several ways (6).
1) Food: people consume meat that contain antibiotic residues or has been contaminated with the resistant bacteria during slaughter
2) Direct contact: farmers and farm workers may become infected by the animals and pass it on to the family and community
3) Environment: bacteria found in the animal manure can contaminate local waterways and groundwater
Recognizing that antibiotic-resistance poses a serious public health threat, the European Union has banned the use of non-therapeutic antibiotics (specifically used in human medicine) in animal feed. Although the United States has yet to pass such a far-reaching policy about antibiotics in livestock production, the FDA did recently ban one class of antibiotics (7). Based on studies showing that high levels of fluoroquinolones (drugs used to treat severe foodborne illness in humans) in the poultry industry led to drug resistance in humans, the FDA finally decided in 2005 to prohibit the use of fluoroquinolones in animal husbandry.
1. Boyd W. 2001. Making meat: science, technology and American poultry production. Technology and Culture 42:631-64.
2. Health Care Without Harm. Antibiotic Resistance and Agricultural Overuse of Antibiotics. 2005.
3. Anderson AD, McClellan J, Rossiter S, Angulo FJ. 2003. Public health consequences of use of antimicrobial agents in agriculture. In: The Resistance Phenomenon in Microbes and Infectious Disease Vectors: Implications for Human Health and Strategies for Containment: Workshop Summary (Washington, D.C.: National Academies Press, p.231-43). Accessed March 14, 2007.
4. World Health Organization, Food and Agriculture Organization of the United Nations, and the World Organization for Animal Health. 2003. Expert Workshop on Non-Human Antimicrobial Usage and Antimicrobial Resistance, Geneva, 1-5 December. Accessed March 14, 2007.
5. World Health Organization. Use of antimicrobials outside human medicine and resultant antimicrobial resistance in humans. Accessed March 27, 2007.
6. Sustainable Table: Antibiotics. Accessed March 14, 2007.
7. The Humane Society of the United States. 2007. An HSUS Report: Human Health Implications of Non-Therapeutic Antibiotic Use in Animal Agriculture. Accessed March 13, 2007.