In a major new statement about the overuse of antibiotics in agriculture, the World Health Organization is urging livestock agriculture and fish farming worldwide to sharply cut antibiotic use, reserving the precious drugs for animals that are sick and then choosing only antibiotics that are not important to human medicine.
The sweeping recommendations, which go further than regulations created by governments, including the United States, were released today at a press conference at WHO headquarters in Geneva. A summary of the recommendations was provided to reporters in advance.
“Scientific evidence demonstrates that overuse of antibiotics in animals can contribute to the emergence of antibiotic resistance,” Dr. Kazuaki Miyagishima, the WHO’s director of food safety and zoonoses, said in a statement that was distributed with the summary. “The volume of antibiotics used in animals is continuing to increase worldwide, driven by a growing demand for foods of animal origin, often produced through intensive animal husbandry.”
Since antibiotics were first introduced in the 1940s, they have been used not just to treat animal diseases but to speed up meat production and make it less expensive by forcing animals to put on weight more rapidly and protecting them from infections passed by other animals in crowded conditions. Those last two uses, growth promotion and prevention, require doses of the drugs that are much smaller than the doses needed to cure diseases, and thus are more likely to encourage the emergence and survival of antibiotic-resistant bacteria.
And since the 1950s, antibiotic-resistant bacteria originating in animals given growth-promotion and preventive doses have caused epidemics of drug-resistant infections in people, both foodborne diseases and other illnesses that have no obvious connection to farms. In 2013-14, for instance, a strain of drug-resistant Salmonella that was traced back to a California chicken processor sickened more than 600 people across the United States. In 2015, researchers found bacteria resistant to one of medicine’s few last-resort antibiotics in people, animals, and retail meat in China. That resistance, conferred by a gene called mcr-1, has since spread across the world, including to the U.S.
Over the decades, some governments have restricted antibiotic use in livestock: the UK in 1971, Scandinavian countries in the 1980s, and the 26 countries in the European Union in 1999 and again in 2006. The U.S. announced its own restrictions in 2013, which took effect in January of this year. But most of these controls address only growth promotion, and almost none deal with the problem of nations with strict controls being vulnerable to resistant bacteria leaking from nations that are lax.
The new WHO recommendations aim to tackle those problems. They divide antibiotics into categories based on the need to preserve them for human medical use, such as least important, medically important, and critically important. Then they recommend that:
- All use of medically important antibiotics in animals should be reduced
- No medically important antibiotics should be used for growth promotion
- No medically important antibiotics should be used for disease prevention
- No critically important antibiotics should be used in animals, not even for treatment of diagnosed diseases
The guidelines also recommend that no human-use antibiotics should be used in agriculture if they are not being used already, and no newly developed human-use antibiotics should be allowed into agriculture.
In 2015, researchers estimated the global use of antibiotics in livestock at approximately 63,151 tons, and predicted that would rise 67 percent by 2030, doubling in developing nations where economic growth is allowing residents to begin buying more meat. The new recommendations could slow that trend, because they recommend global restrictions on preventive uses as well as growth promotion.
But the goal of the new recommendations is not only to reduce antibiotic use in livestock, but also to reduce the flow of antibiotic-resistant bacteria from farm animals to humans. A paper published today in the journal Lancet Planetary Health, to coincide with the WHO announcement, surveyed 179 scientific studies on antibiotics in livestock and found that reducing antibiotic use also reduces the occurrence of resistant bacteria in animals and in people.
The recommendations are only advisory; the WHO has no power to compel action in the nations that make up its World Health Assembly. Nevertheless, researchers and advocates who track animal antibiotic use said this is a promising step.
Lance Price, founding director of the Antibiotic Resistance Action Center at George Washington University, said the recommendations “represent something that we can point governments around the world to, where we can say: Here is a simple set of guidelines to reduce unnecessary risk from unnecessary use in animal production.”
Governments, Price noted, have often not been leaders in the fight against antibiotic resistance, because they fear pushback from agriculture and food-production industries. But as concern about antibiotic resistance has risen worldwide — in 2016, the G7 and G20 groups of nations and the General Assembly of the United Nations all passed resolutions vowing action on antibiotic overuse — governments also have faced pressure from the medical field and from citizens to make changes. “This gives governments something to fall back on,” he said. “If they want to be seen as progressive, as pro-public health, they can use this to say the world is moving this way.”
By restricting categories of drugs, the recommendations go further than the new U.S. rules, which banned growth promotion and put preventive use of antibiotics under the control of veterinarians.
“We need to make sure these recommendations are put into practice, so we should urge the Food and Drug Administration to form concrete policy around them as soon as possible,” said Matthew Wellington, the antibiotics program director for the nonprofit U.S. PIRG. The U.S. rules “were a good step forward,” he said, “but to make sure we keep antibiotics effective for the future, we need to move forward to prohibiting antibiotic use in animals that are not sick.”
Maryn McKenna is the author of Big Chicken: The Incredible Story of How Antibiotics Created Modern Agriculture and Changed the Way the World Eats. She writes regularly about antibiotics and agriculture for Ag Insider.