The Food and Drug Administration's latest move concerning the use of antibiotics in farm animals garnered a good deal of praise last week, but public health advocates say much more is needed.
While such advocates welcome the FDA's proposed partial ban on farm use for one family of drugs important in treating human bacterial infections, they warn that it would do little to combat the overall rise of antibiotic-resistant superbugs such as Methicillin-resistant Staphylococcus aureus (MRSA).
And they were skeptical of the administration's commitment to this larger concern. Avinash Kar, an attorney with the Natural Resources Defense Council, went so far as to suggest the agency's announcement was "meant to distract attention from its effort to sweep the broader issue under the rug."
Cattle, swine, chickens and other livestock receive an estimated 80 percent of the nation's antibiotics, according to the FDA. Whether used to treat our future food, prevent the spread of disease in cramped conditions or simply to promote growth, animal antibiotics are thought to affect human health via multiple pathways: direct or indirect contact with food, water, air or anywhere manure goes.
Kar points out that the targeted drugs, cephalosporins, make up just a fraction of 1 percent of total antibiotic use in livestock -- and only a fraction of these drugs are used in ways that would be prohibited if the rule goes into effect as planned this April. What's more, as noted by Steve Roach, public health program director for the advocacy group Food Animal Concerns Trust, producers could simply replace cephalosporins with gentamicin, another class of antibiotics that is also critical for human medicine.
As with any antibiotic, misuse and overuse of the drug could speed up the development of resistance: Bacteria that can withstand the drugs will survive and reproduce, while their antibiotic-susceptible counterparts will evolve out of the picture.
Compounding the issue is the ability of bacteria to share their drug-evasion secrets with one another. In other words, the use of any one antibiotic can yield resistance to multiple antibiotics.
Fortunately, evidence also suggests the drugs can be redeemed. "For many classes of antibiotics, if we stop using them, the less powerful bacteria will refill that void," said Gail Hansen, senior officer with the Pew Campaign on Human Health and Industrial Farming. "That is the good news. But we have to be very serious about trimming use."
As Tom Philpott reported for Mother Jones, it appears that the use of cephalosporins in livestock is already on the decline, while treatment with other common classes important for human medicine such as tetracyclines and penicillins is steadily rising. Between 2009 and 2010, use of cephalosporins in food-producing animals dropped by 41 percent; use of penicillins and tetracycline meanwhile rose by 43 percent and 21 percent, respectively.
Turns out, these two burgeoning drug classes were central to a decades-old promise retracted by the FDA last month. As HuffPost reported, the agency committed in 1977 to limit the use of antibiotics in animals but never took any action.
In contrast to the FDA's current "fanfare about protecting public health," said Roach, the agency simply slipped a notice into the federal register regarding the withdrawal -- right before Christmas.
Cephalosporins, a young class of antibiotics, are already only approved for certain treatments in livestock, and only with a veterinarian's prescription, said Mike Taylor, deputy commissioner at the FDA. Under the new rule, his agency would have authority to prohibit off-label uses that pose a risk to public health, as well as to restrict changes to the dosing or route of administration.
Tetracyclines and penicillins pose a completely different challenge and regulatory process, Taylor said. The antibiotics have been approved since the 1950s for relatively broad uses without need for veterinarian supervision. In fact, the majority of these antibiotics are given to the animals through their feed or water -- usually at very low doses -- to promote the animal's growth.
Taylor noted that addressing such old drugs, with their grandfathered-in approvals, is difficult. "Frankly, the FDA has struggled with this for a long time," he said, pointing to a "very lawyer-intensive" regulatory process that has "historically taken years to complete."
The agency's new strategy is simply to ask industry to discontinue use of antibiotics as growth promoters. "We haven't taken regulation off the table, but we think we can make progress more rapidly working through a voluntary process," Taylor said. "The FDA is very committed to addressing the resistance issue in a number of different settings, and addressing the fact that older approved uses may be presenting resistance problems."
Taylor added that the voluntary guidance drafted in June 2010 will be finalized in the "not too distant future," though the NRDC notes that a year ago he said the finalization would be coming by last June.
Stuart Levy, a Tufts University microbiology professor who focuses on antibiotic resistance, is optimistic. "I believe that we are seeing a movement of the FDA toward improving antibiotic use in animal husbandry," he said. Levy called the cephalosporins decision an "important and monumental first step" and said he thinks that the United States will "follow Europe with a ban of antibiotics as growth promotants."
Members of the food animal industry, on the other hand, continue to refute the need for such regulation. "The impression out there of our use of antibiotics at low levels is pretty overstated," said Michael Apley, a professor at the Kansas State University College of Veterinary Medicine.
"There is no conclusive scientific evidence indicating the judicious use of antibiotics in cattle leads to antimicrobial resistance in humans," Mary Geiger, spokeswoman for the National Cattlemen's Beef Association, said in a statement last week.
"It's sometimes difficult -- and part of what makes the regulatory process difficult -- to link any particular application to a particular disease outcome," Taylor acknowledged, adding that data is also lacking regarding how producers use the antibiotics. But as for the dire issue of antibiotic resistance and the role played by use in livestock overall, he said, "there is little doubt in the scientific community."
According to a report published by the Government Accountability Office in September, federal inaction has hindered scientists studying the connection between bacterial resistance to antibiotics and the use of drugs on livestock.
Industry representatives also suggest that eliminating further approvals for non-therapeutic uses of antibiotics would make it hard for producers to keep animals healthy. "The judicious use of antibiotics is just one of the important tools cattlemen use to provide a comprehensive herd-health plan to prevent problems and treat animal health issues," said Geiger.
But even if a producer doesn't have an alternate antibiotic available, prominent organic veterinarian Hubert Karreman suggested that they could keep animals healthy simply through better sanitation, a high forage diet and exercise.
"As far as antibiotics go, you don't need them as much in the first place in organics," said Karreman, who also uses a range of alternative treatments, including botanicals, to treat infectious diseases and other ailments.
If a conventional herd converts to organic, he said, his vet bill is typically cut by between 70 and 75 percent: "The closer you can mimic mother nature, the fewer problems you will have."
"Time is running out," said Hansen of the Pew Campaign. "The longer we wait, the closer we come to the end of being able to use antibiotics."
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