The Food and Drug Administration allowed 30 potentially harmful antibiotics, including 18 rated as "high risk," to remain on the market as additives in farm animal feed and water – despite an internal review that raised significant red flags, according to agency records obtained recently by the Natural Resources Defense Council.
The data show the use of these drugs in livestock likely exposes humans to antibiotic resistant bacteria through the food supply.
The FDA’s scientific reviews of these antibiotics occurred between 2001 and 2010, but the drugs remain approved and, in many cases, on the market for use in industrial animal agriculture operations, the documents show.
"The evidence is clear,” said Carmen Cordova, microbiologist for the council and the lead author of its analysis. “Drug makers never proved safety. And FDA continues to knowingly allow the use of drugs in animal feed that likely pose a ‘high risk’ to human health.”
This is a breach of the agency’s responsibility and the public trust, Cordova said.
“This discovery is disturbing but not surprising given FDA’s poor track record on dealing with this issue,” she said. “It’s just more overwhelming evidence that FDA – in the face of a mounting antibiotic resistance health crisis – is turning a blind eye to industry’s misuse of these miracle drugs.”
The FDA’s documents, featured in the council report “Playing Chicken with Antibiotics,” show safety reviews of drugs in the penicillin and tetracycline drug classes – antibiotics considered important to human medicine, which together make up nearly half of all antibiotics used in animal agriculture in the United States.
The documents, obtained through a Freedom of Information Act lawsuit filed by council, reveal:
- None of the 30 antibiotics would likely be approved as new additives for livestock use if submitted under current FDA guidelines, because drug makers haven’t submitted sufficient information to establish their safety.
- Eighteen of the 30 antibiotic feed additives reviewed – nearly two out of three – were deemed to pose a “high risk” of exposing humans to antibiotic resistant bacteria through the food supply and of adversely affecting human health.
- Drug manufacturers never submitted sufficient information for the remaining 12 products to establish safety, meaning there’s no proof of their safety for humans when used in animal feed and the products couldn’t be approved today.
- Twenty-nine of the reviewed additives fail to satisfy the FDA’s first version of safety requirements from 1973.
The significance of these findings extends beyond the 30 antibiotic feed additives reviewed, she said.
Scientific work on bacterial cross- and co-resistance has established that the misuse of one antibiotic can lead to bacterial resistance in other antibiotics. As a result, the 30 penicillin- and tetracycline-based animal feed additives in this analysis could reduce the effectiveness of a range of other medically important antibiotics that are only used to treat people.
The FDA first recognized the risks from the use of antibiotics in animal feed in 1977 when it proposed to withdraw approvals for animal feed containing penicillin and most tetracyclines.
The council won a lawsuit against the FDA for failing to follow through and address the threat posed by the misuse of penicillin and tetracyclines in the livestock industry. Instead of acting on its own scientific findings and following the court ruling, the FDA appealed, and a decision is now pending before an appeals court.
The World Health Organization lists penicillins as critically important for human medicine and tetracyclines as highly important. Penicillins are used to treat bacterial meningitis and syphilis in humans. Tetracyclines are prescribed for eye infections, Lyme disease, gonorrhea, and chlamydia. FDA also recognizes both as highly important.
Unfortunately, both penicillins and tetracyclines are no longer effective for treating some infections because of high levels of resistance in bacteria, brought on, in part, due to their widespread use in industrial farms, Cordova said.
Increasing resistance to these drugs decreases the options available for human treatment, she said
The FDA’s failure to act on its own findings on the 30 reviewed antibiotic feed additives is unfortunately consistent with the agency’s decades-long history of failure to effectively deal with this issue, Cordova said.
Today, 70 percent of all medically important antibiotics sold in the U.S. are sold for use in livestock production, not humans.
For decades, health groups, medical doctors, and other scientists from the American Academy of Pediatrics to Infectious Disease Society of America have called attention to problem, stating that “overuse and misuse of important antibiotics in food animals must end, in order to protect human health.”