Recently, we gathered four experts at Duke Medical School in Durham, NC to talk about the dangers of antibiotic overuse. At this "Preserving Antibiotics: A Public Health Imperative" event, they examined the growing issue of antibiotic resistance, how animal farming practices are making things worse, and what we can do to solve the problem.
To watch this great presentation, go to the video here.
To read more about it, here's a short summary (with thanks to my colleague Miles Pulsford.)
Dr. Vance Fowler - co-director of the Antibacterial Resistance Leadership Group coordinating research around the country on antibiotic resistance - kicked things off with the problem: increasing antibiotic resistant infections and fewer new antibiotics. He discussed the reluctance of pharmaceutical companies to invest in the development of new antibiotics. "Pharma is getting out of this game." At the time of discovery, a new IV antibiotic is worth approximately negative $50 million to a drug company. By comparison, new musculoskeletal drugs have an estimated discovery value of $1 billion.
Some antibiotic resistance comes from the healthcare industry. According to Dr. Deverick Anderson, head of Duke's antibiotic stewardship program, two thirds of all hospital patients will receive an antibiotic, and as many as 50 percent of those prescriptions are unnecessary. All antibiotics exert selection pressure for antimicrobial resistance, and improper use has an exponentially greater effect. Most infection control and outbreak prevention procedures were developed before we fully understood resistance, and practices have been slow to change.
But healthcare-related resistance is only part of the problem.
More than 60 percent of the infectious diseases humans can acquire are zoonotic. Professor Michelle Nowlin from Duke Law School explained that nearly 80 percent of all US licensed antibiotics are used by the food animal industry, including many drugs that are critical to human medicine. The least predominant animal use is the treatment of actual disease. More often, these antibiotics are used at sub-therapeutic doses for the purposes of growth promotion and disease suppression. These doses harm vulnerable bacteria, reducing competition and making growth easier for the ones that are developing resistance.
It is very easy for these resistant microbes to reach humans.
One common route is through the distribution of livestock waste. A typical swine factory farm - often called a CAFO for Concentrated Animal Feeding Operation - might contain five thousand hogs. Each animal creates as much feces as three humans, which means each CAFO outputs as much fecal matter as an entire city of people - without any of the same sewage treatment facilities and regulations. Instead, the waste is stored in open lagoons, and eventually gets sprayed onto fields as fertilizer, if it doesn't first leak out into the soil or spill into nearby waterways.
Most states do not have significant minimum separation distances between CAFOs and other properties. In North Carolina, the farms and lagoons must be 100 feet from houses and schools, and waste may be sprayed as close as 25 feet.
CAFOs are predominantly located in low-income, minority regions. People in these areas have less access to healthcare and transportation, and are less able to escape the conditions of their communities. Studies have shown increased incidence of community-acquired MRSA downwind of CAFO facilities.
"This whole concept of patients acquiring these multi-drug-resistant pathogens in the community and then coming into the hospital with them, it's a paradigm shift, one that completely overthrows what we typically consider to be where these infections were occurring." Dr. Anderson described the medical community's reaction to discovering this side of antibiotic resistance. "It essentially wrecked, to some extent, our standard thinking about what kind of infection a patient might have when they come in."
"We're not in charge, folks."
Dr. Blackwell, chief veterinarian for the Humane Society Veterinary Medical Society, holds government accountable for failing to protect citizens from this epidemic.
It was not until 1962 that Congress gave the FDA authority to require that new drugs be proved effective before receiving approval. Before the stricter rules were in place, many dangerous antibiotics were approved for use in livestock. Unfortunately, once a drug is approved, the burden rests on government or the people to prove that it is dangerous before it can be revoked.
In 1977, the FDA first proposed banning over-the-counter sale of penicillin and tetracyclines. They have yet to succeed. CAFO operators are still not even required to report what drugs they use.
So how can we solve this crisis? According to Dr. Fowler and Dr. Blackwell, the answer is legislation. The FDA is fully aware of the problem, but it can only act as authorized by Congress. This country needs new legislation that would give the FDA power to ban sub-therapeutic use of human antibiotics in animal medicine.
In 1999, Denmark banned all nontherapeutic uses of antibiotics in agriculture and started a transition to healthier animal husbandry practices. Today, the country is the largest pork exporter in the world. Giving our farm animals more room, reducing their stress, and properly managing their waste would go a long way toward reducing disease and therefore our need for routine antibiotic use.
Finally, thanks to the Duke Environmental Law Society and Duke Careers in Internal Medicine Interest Group for hosting and to Panera Bread for donating the antibiotic-free dinner.