The FDA must act on its 35-year-old proposal to ban certain antibiotics from animal feed, ruled a federal court Thursday. 

In 1977, FDA determined that 3 antibiotics were likely contributing to drug-resistant bacteria strains in humans and should be reserved for therapeutic uses only. But the agency never held the drug company hearings required to put this proposal into place, and in December of 2011 it revoked these approval withdrawals altogether.

But this week a court decision forced FDA to revive its plan to limit the 3 drugs – penicillin and two types of tetracycline – pending hearings with industry.

The suit was filed by a coalition of 5 nonprofit organizations including the National Resources Defense Council (NRDC), the Center for Science in the Public Interest, the Food Animal Concerns Trust, Public Citizen and the Union of Concerned Scientists.   

Citing a growing body of evidence linking drug-resistant human bacteria to animal antibiotics, the groups argued that once FDA determined that subtherapeutic (non-treatment) uses of penicillin and tetracyclines could be dangerous to human health, it had an obligation to see through its proposal to restrict these drugs.  

The magistrate judge’s ruling does not order FDA to ban subtherapeutic uses of these drugs, but rather to carry out the hearings with drug companies needed to make its final decision. And the burden of proof will be on industry to show that the antibiotics in question are safe for human health when used in animal feed.  

“The [FDA] Commissioner has adopted and, therefore, issued findings and the mandatory withdrawal proceedings have been triggered,” said the decision, written by Magistrate Theodore Katz.  

The suit’s plaintiffs were pleased with its results, but stressed the need for FDA to act on them going forward.

“This ruling changes the landscape at FDA, making it clear that agency has a statutory obligation to use its legal authority to cancel the approvals for uses of veterinary drugs the agency has found to be unsafe,” said Margaret Mellon, Director of the Union of Concerned Scientists in a statement Friday. “The ruling calls into question policies that rely on companies to voluntarily withdraw label claims.”

“It’s about time,” said representative Louise Slaughter (D-NY) of the ruling. “The FDA has been dragging its feet on this for 35 years. We’ve all known that this is a public health issue for quite some time. Of course if an animal is sick, it should be treated. But the evidence for ending the daily dosing of antibiotics to otherwise healthy animals is overwhelming. I’m pleased to finally see some progress and I can only hope that we see swift action from the FDA on this looming crisis.”

According to the Union for Concerned Scientists, 70 percent of antibiotics distributed in the U.S. are used to promote growth or to prevent the spread of disease among animals living in crowded or unsanitary conditions. Just 10 percent of these drugs are used to treat sick animals, and the remaining 20 percent go to humans. 

Tetracycline and penicillin are commonly used to promote growth in chicken, turkeys and pigs. The former is also given to cattle and sheep as a growth agent. In 2010, over 12 million pounds of tetracycline were given to animals, compared to the 100,000 pounds sold for human use. 

That year almost 2 million pounds of penicillin went to livestock while 1.5 million pounds were given to humans.