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How Much Do Antibiotics Used on the Farm Contribute to the Spread of Resistant Bacteria?

The substantial amounts of antibiotics given to farm animals are among the reasons bacteria are becoming more resistant to medicine's disease-fighting vaccine arsenal

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Dear EarthTalk: I understand that the use of antibiotics in raising farm animals is threatening to make bacteria overall more resistant to antibiotics, which has serious life and death implications for people. Can you enlighten and advise what is being done about this?—Robert Gelb, Raleigh, N.C.

Most medical doctors would agree that antibiotic drugs—which stave off bacterial infections from staph to salmonella to bacterial pneumonia—are among the most important tools in modern medicine. But public health advocates, environmentalists and even many doctors worry that our society’s overuse and misuse of antibiotics is making bacteria more resistant and thus limiting the effectiveness of these lifesaving drugs.

Bacterial resistance to our antibiotics simply means longer, more serious and more costly illnesses. The Alliance for the Prudent Use of Antibiotics, a nonprofit that conducts research around the world on antibiotic resistance, estimates that antibiotic resistance has been responsible for upwards of $16 billion annually in extra costs to the U.S. health care system in recent years. The U.S. Centers for Disease Control and Prevention (CDC) considers antibiotic resistance one of its top concerns.


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While misuse of antibiotics for human health problems is definitely a concern—those with a valid need for antibiotics who don’t finish off their prescriptions, for example, could effectively help bacteria develop resistance and make it stronger for when it infects its next host—a larger issue is the misuse of antibiotics to treat the common cold and flu and other viral infections which do not involve bacteria. The more antibiotics we use willy-nilly, the faster bacteria will develop resistance, rendering many of the drugs modern medicine has come to rely on obsolete.

Of even greater concern is the preponderance of antibiotics used down on the farm. “Antibiotics often are used on industrial farms not only to treat sick animals but also to offset [the health effects of] crowding and poor sanitation, as well as to spur animal growth,” reports the Pew Campaign on Human Health and Industrial Farming. Indeed, researchers estimate that up to 70 percent of all antibiotics sold in the U.S. are given to healthy food animals to artificially expedite their growth and compensate for the effects of unsanitary farm conditions. “The routine use of antibiotics in food animals presents a serious and growing threat to human health because it creates new strains of dangerous antibiotic-resistant bacteria,” says Pew.

So what can we do to curtail the overuse and misuse of antibiotics? For one, we should not prescribe or use antibiotics to (mis)treat viral infections. Beyond being conscientious with our own bodies, we should also urge farmers to reduce their use of these drugs. Pew and other groups are trying to muster public support for the Preservation of Antibiotics for Medical Treatment Act (PAMTA, H.R. 1549/S. 619), which if enacted would withdraw from food animal production the routine use of seven classes of antibiotics vitally important to human health unless animals are diseased or drug companies can prove that their use does not harm human health. Hundreds of groups, including the American Medical Association, American Academy of Pediatricians, Infectious Diseases Society of America and World Health Organization support the legislation. Pew is urging concerned citizens to call their Representatives and Senators and advocate for pushing the legislation into committee hearings.

CONTACTS: Alliance for the Prudent Use of Antibiotics, www.tufts.edu/med/apua; CDC, www.cdc.gov; Pew Campaign on Human Health and Industrial Farming, www.saveantibiotics.org.

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