For the past several years, there has been a growing concern about increases in human illnesses that are resistant to antibiotics. Also during that time, there have been attempts to place the blame on U.S. food-animal production. In every Congress since the 106th (1999/2000), legislation has been introduced to ban certain antibiotics for use in livestock and poultry production.

But now there seems to be a real push to secure passage of the “Preservation of Antibiotics in Medical Treatment Act.” Among those efforts have been several recent media stories on antibiotic use in livestock and poultry production, as well as congressional briefings on the issue held by the prejudicially named Pew Commission on Industrial Farm Animal Production. Even the government of Denmark weighed in on the matter.

Antibiotic resistance is the tendency of bacteria to evolve in ways that make antibiotics less effective, or ineffective, in controlling the growth of them. At the core, it’s biologic survivability. While several factors influence resistance, advocacy groups that oppose modern food-animal production have long hyped animal drugs’ role, especially the practice of putting antibiotics in animal feed to spur the rate of growth and to improve feed efficiency.

U.S. livestock organizations have countered that propaganda by pointing to Denmark’s experience following that country’s1998 ban of “antibiotic growth promoters.” Danish pork producers saw increases in piglet deaths and sick pigs, as well as a rise in the amount of antibiotics used to treat animal diseases. It’s worth noting that those are typically drugs also used to treat humans. While the ban raised pork production costs, it has had no positive effect on human health. A U.S. delegation of lawmakers learned as much during last fall’s visit to Denmark.

The Danish National Food Institute, in a letter sent to members of the U.S. House Agriculture Committee, tried to repudiate those claims, saying there have been “creative interpretations” in the United States about Denmark’s ban. Interestingly, the letter and an accompanying presentation included a “CC” to the Pew Commission on Industrial Farm Animal Production.

The presentation argued that the 1998 Danish ban successfully reduced antibiotic use and antimicrobial resistance in farm animals while production increased. But the presentation had its own “creative interpretations,” including cherry-picked data in order to support pre-determined conclusions and a hard-to-defend 1992 base year for its calculations.

Likewise, a recent Associated Press article and a CBS Evening News story relied on unsubstantiated claims linking antibiotic-resistant illnesses in humans, such as methicillin-resistant Staphylococcus aureus — or MRSA — to the use of antibiotics in livestock and poultry production. One even repeated the unsupported assertion that “70 percent of the antibiotics in this country are going to livestock.”

That number, from the controversial Union of Concerned Scientists, cannot be known because there is no data on human antibiotics use. Additionally, UCS included in its calculation antibiotics never used in livestock production in this country.

Antibiotic resistance is a serious problem that, if left unchecked, could adversely affect drugs important to human medicine. But there is no proof that antibiotic use on farms significantly increases resistant bugs in humans. Animal drugs are probably a minor factor at best. A more likely culprit is overuse of antibiotics in human medicine. For example, according to a peer-reviewed paper published in the Journal of the American Veterinary Medical Association, pound-for-pound, people and their pets consume 10 times more antibiotics than food animals.

The Institute of Food Technologists says that correlating the risk of antibiotic use in animals and antibiotic resistance in humans is not possible. In 10,000 investigated human MRSA cases, the Centers for Disease Control and Prevention has found no link to animals. Further, CDC said that if animal-to-human transmission of bacteria such as MRSA is occurring, it is responsible for a very small percentage of all human infections.

Other published, peer-reviewed risk assessments have found similar results. A U.S. Food and Drug Administration assessment found that the types of bacteria in humans and animals were different, meaning the resistant bacteria found in humans were not coming from animals.

As for use in U.S. livestock production, only 13 percent of antibiotics are used for growth promotion. What’s more, the majority of those prevent disease in animals and are not used in human medicine. The bottom line: Resistance would not end even if the growth-promoting animal antibiotics were eliminated.

But the pending legislation would ban more than so-called growth promoters; it would prohibit the use in feed of most antibiotics that help prevent and control livestock diseases. That’s not only bad for animals but also for consumers, because healthy livestock yield safer food. A study by Scott Hurd, DVM, with Iowa State University’s College of Veterinary Medicine, showed pigs that have been sick tend to have a greater presence of food-safety pathogens on their carcasses. An Ohio State University study found that “antibiotic-free” pigs have a higher incidence of zoonotic diseases and parasites than those that receive antibiotics.

Beyond the food-safety implications, a ban on certain animal antibiotics will raise the food production costs and, in turn, retail meat and poultry prices. An Iowa State analysis found that if the United States implemented an antibiotics ban similar to Denmark’s, U.S. pork production costs would rise by as much as $6 per pig in the first year and would cost the industry more than $1 billion over 10 years. Such a ban would cause retail pork prices to increase by 2 percent.

Controls on animal antibiotics in this country are already substantial — tougher, in fact, than controls on human antibiotics. Before being approved for use in livestock, FDA requires manufacturers to show that the drug will not harm human health. There’s also a withdrawal period — time between an animal’s last dose and its slaughter — set for every animal drug.

Additionally, the federal government closely tracks antibiotic resistance through the National Antimicrobial Resistance Monitoring System, a cooperative program involving FDA, CDC and USDA’s Agricultural Research Service. NARMS has been used for more than a decade to track antibiotic-resistant bacteria in humans, animals and retail meats. The program’s data has not shown patterns reflecting that resistant bacteria are routinely being transferred from animals to humans.

While there is little information to make pigs or other food animals the culprits in increasing antibiotic-resistant diseases in humans, the U.S. pork industry isn’t taking the antibiotic-resistance issue lightly. Its Pork Quality Assurance Plus program includes guidelines for using antibiotics in pigs, and the Take Care: Use Antibiotics Responsibly program educates producers on using antibiotics judiciously. The National Pork Board, which administers both programs, also contributed more than $200,000 to study MRSA and pigs.

For its part, the National Pork Producers Council will continue educating lawmakers about antibiotic use in livestock and beating back efforts to remove these important animal-health tools.