Agriculture industry science denial?

June 8, 2011 — Remapping Debate has previously reported on attempts to “repeal” climate science; it appears that the U.S. agricultural industry’s widespread use of antibiotics in animals used for food is another area where science denial is at play.  Even though the U.S. Food and Drug Administration, the U.S. Department of Agriculture, the Centers for Disease Control and Prevention, and the World Health Organization are united in concluding that such use leads to human exposure to antibiotic-resistant bacteria, the industry is actively fighting efforts to restrict the routine, non-medical use of antibiotics in animals, and the FDA has yet to impose a ban.

The problem — which the FDA and sister organizations say is a risk to public health — is already enormous, and it is growing.  According to the CDC, Methicillin-resistant Staphylococcus aureus, an antibiotic-resistant bacteria commonly known as MRSA, kills an estimated 19,000 people per year in the United States. The cost of fighting antibiotic-resistant microbes exceeds $20 billion per year.

Medical misuse of antibiotics in humans is part of the problem.  But another contributor is the misuse of the drugs in food animals. According to the FDA, a staggering 80 percent of the antibiotics used in the United States is used on livestock animals.

Livestock producers do not simply use antibiotics to treat sick animals. They also use antibiotics to promote growth or feed efficiency. The Union of Concerned Scientists estimates that 70 percent of the antibiotics used in the U.S. is used in food animals for non-therapeutic reasons — that is, for reasons other than treating disease. According to the FDA, 90 percent of the antibiotics given to animals is distributed via animal feed or water, a method that critics say is used primarily for non-therapeutic reasons.

A known problem

As early as the 1970s, the FDA recognized that the use of antibiotics in animals for non-therapeutic reasons could promote the development of antibiotic-resistant pathogens that are harmful to humans. In 1977, the agency proposed to withdraw approval for the use of two kinds of antibiotics — penicillin and tetracyclines —in animal feed at sub-therapeutic levels, or at doses too low to treat disease, because it said evidence showed the practice to be unsafe. But Congress recommended that further study be done on the issue and the FDA never acted on that recommendation.

Since then, the evidence showing that the use of antibiotics in animals for non-therapeutic reasons poses a health risk to humans has only gotten stronger. All the while, new strains of microbes that are resistant to an increasing number of drugs are continually discovered.

Scientists believe that antibiotic-resistant bacteria that originate in farm animals can transfer to human populations, either through animal handlers that then spread the pathogens to the general public, or via contaminated meat that is handled or eaten at home.

Scientific opinion is “overwhelmingly in favor of the fact that this broad use of antibiotics in animals is contributing to antibiotic resistant disease in humans,” said Margaret Mellon, director of the food and environment program at the Union of Concerned Scientists. “It just has to be the case. We use the same antibiotics in pork and in cows and in chickens as we do in doctors’ offices, and we’re generating these huge volumes of antibiotic-resistant bugs.”

Mellon summarized the prevailing scientific view that the non-therapeutic use of antibiotics in animals leads to human infections of antibiotic-resistant microbes in prepared testimony for a 2009 congressional hearing. The journal Clinical Infectious Diseases in 2002 wrote in a special supplement that the ‘‘[u]se of antimicrobials in food animals contributes to the growing problem of antimicrobial resistance in animal and human infections,” Mellon said. The World Health Organization in 2003 said ‘‘There is clear evidence of the human health consequences [from agricultural use of antibiotics, including] infections that would not have otherwise occurred, increased frequency of treatment failures (in some cases death) and increased severity of infections,” she added.