The Union of Concerned Scientists (UCS) is calling for widescale government monitoring of the use of antibiotics in livestock. In a report released last week, it says the amounts used far exceed industry estimates and that widespread use is putting human health at risk by encouraging the development of resistant bacteria.
The report estimates that 70% of all antibiotics used in the United States are fed to healthy animals. It urges the Food and Drug Administration (FDA) and the US Department of Agriculture to compel the drug and livestock industries to report the quantities, dosages and treatment periods of all antimicrobials used on food animals.
“Which antibiotics are most in use? Have use patterns changed over time? Why? These are all very basic questions, and in the US, you can't answer them. There are no data compiled by the government either on production or use,” says Margaret Mellon, the report's lead author.
The UCS, which represents about 50,000 US scientists and citizens, timed its report to influence an FDA meeting on 22 January on antimicrobial use in livestock. The report says that, without thorough and reliable data, it is impossible to combat growing antimicrobial resistance in human pathogens.
Industry has in the past resisted providing such data. Livestock and poultry producers have used low-level antibiotics non-therapeutically in animals for decades to promote growth and prevent disease. They argue that restrictions would put meat prices up and compromise food safety.
The UCS report uses publicly available data to arrive at an admittedly approximate estimate that 24.6 million pounds (11,200 tonnes) of antimicrobials are fed to US poultry, pigs and cattle annually for non-therapeutic uses, an increase of 50% since 1985.
Industry sources dispute that number. The Animal Health Institute (AHI) in Washington, which represents the makers of animal drugs, estimated last year that 8,100 tonnes of antibiotics were used for all purposes in animals, of which only 4,200 tonnes are antibiotics also used in humans.
“The assumption is that somehow human health is being compromised,” says John Keeling, who spearheaded the AHI survey. “That has not been demonstrated.”
But Stephen Sundlof, director of the FDA's Center for Veterinary Medicine, says that transmission of antimicrobial-resistant pathogens from animals to humans in the food supply is an established fact, although the degree to which it occurs and the severity of the disease it causes remains in dispute.
Sundlof says that the agency has drafted regulations that will compel companies to make available most of the information that the UCS is calling for.