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Public Radio's Environmental News Magazine (follow us on Google News)

Antibiotic Use on the Farm

Air Date: Week of
In industrial agriculture thousands of animals are housed together, and illness spreads easily. That’s why antibiotics are often given prophylactically. (Photo: Wikimedia Creative Commons)

Eighty percent of antibiotics used in the U.S. are used on livestock to help prevent disease and make them grow large quickly. But some say this low dose, non-medical use of antibiotics in agriculture is causing bacteria to evolve to become resistant and putting human health at risk. As Living on Earth’s Jessica Ilyse Kurn reports, it’s now up to the courts to decide whether to limit the non-therapeutic use of drugs on animals.


GELLERMAN: Penicillin has saved more lives than any other single drug. The world’s first antibiotic was discovered in 1928, but it wasn’t until the 1940’s, on the battlefields of World War II, that penicillin was first used widely to treat infections.


ANNOUNCER: Gangrene from which millions have perished in past wars has been conquered by the miracle of penicillin. Scientists are manufacturing this wonder drug in enormous quantities to meet the demands of the allied armies on every front.

GELLERMAN: Over the years scientists have created many different antibiotics but it’s been an on-going war between the powerful drugs and bacteria that can evolve and become resistant. And one of the main battlefields today - farms where antibiotics are routinely fed to animals.Living on Earth’s Jessica Ilyse Kurn reports.

KURN: In 1951 the Food and Drug Administration approved the use of antibiotics for use in animals after seeing how effective the drugs were in treating human infections. But by the 1970s, the agency started to worry about bacteria resistance and decided to halt the drugs’ non-medical use.

Penicillin was a wonder drug in the 1940s. (Photo: Wikimedia Creative Commons)

KAR: The more you use antibiotics the more antibiotic resistance is likely to occur. And almost 80% of antibiotics used in U.S. are used on livestock.

KURN: That’s Avinash Kar, a lawyer with the Natural Resources Defense Council. In March, Kar won a case in Federal court against the FDA. He charged the agency with failing to enforce their 1977 ban on the non-therapeutic use of penicillin and tetracycline in farm animals.

KAR: We believe that they caved into pressure from industry. And they should have been acting long ago. They say they recognize that this is a risk to human health but we haven’t seen them step forward and put the health of American citizens first.

KURN: Antibiotics are given to farm animals to treat illnesses, much like in humans. But it’s the non-medical uses that the NRDC says are the problem, when farmers put antibiotics in feed and water to keep diseases at bay, and to make the animals grow larger, faster.

KAR: They’re designed to save lives and not fatten pigs and chickens, and yet we’re using more antibiotics on healthy farm animals than on sick people. You’re not treating a disease but basically trying to compensate for crowded and unsanitary conditions.

A beef feedlot in the Texas panhandle. (Photo: Wikimedia Creative Commons)

KURN: On industrial farms, animals can live by the hundreds, often thousands. In such crowded conditions if one chicken gets sick, there’s a high chance illness will spread. So low doses of preventative drugs are given to the entire flock. Glenn Morris is a physician, and the director of the Emerging Pathogens Institute at the University of Florida. He says it’s these low doses that are the problem.

MORRIS: The best way to develop a resistant strain is to treat bacteria with low doses of antibiotics; low enough that you aren’t immediately killing the bacterium, but you are providing selective pressure for the appearance of resistant strains. So unfortunately that’s exactly what we’re doing with sub-therapeutic use in farm animals.

KURN: Morris says the numbers of antibiotics in the environment are wreaking havoc for humans. The Infectious Diseases Society of America reports that drug resistant infections kill nearly 100,000 Americans each year and estimates that the financial burden to the healthcare system is as high as 34 billion dollars annually. But the National Pork Producers Council chief veterinarian Liz Wagstrom insists that giving antibiotics to farm animals doesn’t endanger humans. She says the Council has examined the risks.

WAGSTROM: The last risk assessment that was done on penicillin said between zero and one person per century might have disease that would be untreatable or difficult to treat because of penicillin resistance due to use of that compound in animal agriculture.

KURN: Industry officials say the problem is with doctors over-prescribing antibiotics to humans. But according to the FDA, 7 million pounds of antibiotics were given to humans in 2009, while 28 million pounds were sold for use on farm animals that same year. Glenn Morris says this means that physicians find themselves in a war with bacteria, trying to constantly stay one step ahead. And as in most wars, a winner starts to emerge.

MORRIS: What we are seeing as I look back over the last several decades is that antibiotic therapies, which worked just fine 10 years ago, even five years ago, now suddenly we’re having to go to further drug combinations, and some of the older antibiotics that we had stopped using because they had significant side effects, now sometimes they’re the only thing that will work. It’s tougher because your options are more limited.

KURN: Resistant bacteria travel from the farm to the general human population in a variety of ways. One route is through farm workers, but the broader path is through our food. A 2011 study in the journal Clinical Infectious Diseases, found that nearly half of the meat and poultry in U.S. grocery stores is contaminated with Staph infection, and more than half of those bacteria were multi-drug-resistant. When meat is properly cooked, Staph is usually killed, but there’s still a risk of contamination.

A scanning electron micrograph (SEM) shows methicillin-resistant Staphylococcus Aureus bacteria, commonly referred to as MRSA. (Photo: Wikimedia Creative Commons)

Morris says it’s possible to reverse this trend. He gives the European Union as an example, where non-medical uses of antibiotics were limited starting in the early 1990’s and then banned in 2006. Since then, he says, there have been clear improvements in antibiotic resistance in Europe.

MORRIS: What Europe has clearly shown is that you can still raise chickens just fine, or pigs, or cattle, without the growth enhancers. There are data suggesting that you do have to be a little more careful in the way you raise animals. Using antibiotics gives you the ability to crowd animals together a little bit more and to have practices in your animal agriculture, which may not be quite as sanitary.

KURN: But others argue when Europe pulled the plug on the non-medical uses of antibiotics on animals, there were unintended consequences. In Denmark, the hogs got sick and the use of medicinal antibiotics increased. Scott Hurd is a professor of veterinary medicine at Iowa State University and the former Deputy Undersecretary of Food Safety at the USDA. He’s looked carefully into what happened in Denmark.

HURD: What was interesting, and I think surprising, was that the amount of product used to treat sick pigs actually doubled after the ban. What that tells me is those preventative uses were indeed important.

KURN: Preventative medicine is important to animals says Hurd—so important their use outweighs potential resistance. And supporters of prophylactic use of drugs, including Liz Wagstrom from the National Pork Producers Council, say without antibiotics it will be harder and more costly to raise animals.

WAGSTROM: What we would end up with is more sick pigs, less efficient growth. We’d likely contribute to a higher cost of food. So I think as the pork industry, without this idea that we’re going to improve public health, it makes having more sick pigs and a higher cost of production a difficult concept to handle.

KURN: The Natural Resources Defense Council won their suit against penicillin and tetracycline, and the FDA is deciding whether to appeal the court’s ruling. But as farmers turn to other antibiotics, the NRDC is not far behind in filing additional suits. In a second brief, the organization has asked the FDA to limit all non-therapeutic drugs on animals. A ruling is expected in the next few weeks. For Living on Earth, I’m Jessica Ilyse Kurn.



NRDC legal blogger Avinash Kar on his case against the FDA

Dr. Glenn Morris, Emerging Pathogens Institute, FSU

Food Risk Modeling and Policy Lab at Iowa State University

National Pork Producers Council


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