There's not the same control [on antibiotic use in animals] as there is in people
Approximately 80 percent of antibiotics are used on animals, not humans. "There's not the same control or restriction on their use as there is in people," says Stuart Levy, a microbiologist at Tufts University who has spoken out against the overuse of antibiotics for 30 years. And some of the drugs used on animals are medically important for humans. So when they're overused in animals, we humans end up with bacterial infections that our drugs can't treat.
Resistance occurs when bacteria encounter antibiotics in their environment in doses too small to kill them. This allows them to adapt to the drugs in ways that help them resist to larger doses in the future. And although many emerge from human antibiotic use (about 50 percent of people who take antibiotics don't actually need them), it's thought that the large quantities of antibiotics given to livestock for disease prevention, treatment, and growth purposes leads to people ingesting bacteria that doesn't respond to antibiotics. That's why some epidemiologists and infectious disease experts are stung that the agricultural uses of antibiotics didn't receive more attention in the bill.
Obama's plan largely glossed over the use of antibiotics in agriculture. Besides banning their use for growth purposes — something the FDA had already announced it would do in December 2013 — it doesn't address the preventative use loopholes that remain. "I think it's a step in the right direction," Levy says, "but we wanted a leap."
Other scientists were more blunt in voicing their discontent. "It reads as if it had been written by someone either from the meat industry, or the vet drug industry," says James Johnson, an infectious disease researcher at the University of Minnesota. Although the government's strategy bans the use of antibiotics for growth purposes, Johnson says, one could easily continue to use them for that purpose, and call it a preventative measure. "The language is the standard party line about how antibiotic use in animals makes stronger animals — that it's all wonderful. But that's just one perspective, and I don't think it's a science-based perspective."
A better strategy, would be to change the way meat is produced in the US, says Lindsay Grayson, an infectious disease researcher at the University of Melbourne, in Australia. Large-scale chicken farms, for instance, can scale down their use of antibiotics by thinking in terms of infection control. Physically separating different batches of birds and minimizing overcrowding is key, he says. That way, when one bird gets sick, the bird can be diagnosed before disease spreads. "No one is against using antibiotics to treat sick animals," he says, "but we shouldn't endorse mass preventive use on a daily basis simply because your farming practices allow for rapid spread."
Not everyone is of this opinion, however. Christine Hoang, assistant director of scientific activities at the American Veterinary Medicine Association, says the goals outlined by the Obama administration are good enough. They reflect the FDA's stance on antibiotics use in food production and the intention to phase out growth promotion uses, she says. "There aren't really any loopholes," Hoang says. Under Obama's plan, drugs will be used to treat and prevent disease, she says, and there will be more veterinary oversight. "I don't think we should limit antibiotic use any more. It's a great detriment to us as a profession, as well as to animal welfare, to restrict them further."
Hoang's take was echoed by Paula Cray, leader of the USDA's Bacterial Epidemiology and Antimicrobial Resistance Research Unit, who added that the planet will be home to 4 billion additional humans by 2100, all of which will expect to be fed. "There's a need to double the production of animal protein," she says. And that kind of production — the kind that presumes that every human will want to eat meat — will take a certain capacity, one that may not be compatible with less crowded animal housing practices.
This might very well be the thought process behind the US antibiotic plan. Instead of trying to change farming practices — which guarantees a painful fight with large agricultural corporations — the government has opted to push for the development of new drugs, ones that will be used on either humans or animals, but not both. Accordingly, the US has promised to support basic research and "leverage existing partnerships" that will help reduce the obstacles that pharmaceutical companies face during clinical trials. The White House also pledged to inject drug research with an additional $800 million a year to develop new medicines. That may not be enough.
There aren't really any loopholes
"I'm not sure that the incentive part will get the pipeline full," says Henry Chambers, chair of the Antimicrobial Resistance Committee at the Infectious Diseases Society of America. Developing a new drug costs about $5 billion. When companies make that kind of an investment, it's because they expect sales numbers for the drug to be high enough to turn a profit. But when doctors encounter a new antibiotic, their instinctive reaction is to use it sparingly, so they have it on a rainy day.
"The first inclination is to say, 'Wow this is really good, we better not use it because resistance will occur,'" Chambers says. Besides, new antibiotics might not be better than the old ones, he says. And some, such as ciproflaxin and daptomycin, may have serious side-effects. Doctors who choose new antibiotics therefore end up making their patients purchase drugs that are probably just as effective, but far more expensive.
When you look at it that way, Chambers says, the incentive for doctors to use new drugs isn't all that high. And without doctors pushing the drugs out to patients, drug companies aren't as likely to profit off their $5 billion investment. For many companies, even the government incentives don't make antibiotics as appealing as blood-pressure pills and cancer medications.
The US can't fight off superbugs alone, of course. Countries need to talk to each other when they encounter new health-care challenges, or when they find solutions. The sooner scientists and policy-makers know about new resistance, the easier it is to slow the organisms' spread. Right now, there's no fast way to do that, Cray says.
Also crucial are better diagnostics. Remember the 50 percent of people who take antibiotics and don't need them? Cray, Levy, and Johnson all say that aiming antibiotics only at people who need them is key. To do that, faster tests may be needed to separate people who really require antibiotic treatment from those who don't. Right now, doctors don't always determine whether something is a bacterial infection before prescribing antibiotics, if they test at all.
"With our current tests, even if they're done, many take several days and by then people have already taken antibiotics," Johnson says. Quicker tests are starting to trickle down to physicians, he says, but they rarely come cheap. Finding ways to accelerate test development — and lower prices — could do a lot more than finding novel antibiotics. But Obama's plan only provides $20 million for the development of a rapid diagnostic tests, a small sum when compared to the $800 million going to drug development.
Since antibiotics were discovered in 1942, we've wasted a lot of them, Grayson says. "If you were an alien standing on Mars, and looking down on the Earth — on humans — you would say, 'What an idiotic species!'" So it's good that the president is doing something, even if it isn't as comprehensive as experts at hoped. At least it's a start, Grayson says.
Of course, one of the most important steps to take in curbing antibiotic resistance remains the one that has evaded us for over 70 years: education. Teaching the public about proper antibiotic use "really has to be developed," Cray says. Even basic levels of public education on antibiotic use are lacking. For instance, says Cray, lots of people still think antibiotics will help them get over a cold. That's wrong, since colds are caused by viruses, not bacteria. The real preventive strategy for viral infections is usually a vaccine, but lots of people go to doctors and ask for antibiotics anyway; sometimes doctors even prescribe them. That contributes to antibiotic resistance too.
"I don't think everyone needs a deep understanding, but we should have some idea of how things work," he says.