How using antibiotics in agriculture fuels resistance beyond the farm


Over the past week, PBS NewsHour covered one of the most pressing health issues that we face today: antibiotic resistance. Whenever we use antibiotics, we potentially fuel the growth of antibiotic-resistant bacteria (a.k.a. superbugs). In societies – like the U.S. – where antibiotics are used routinely in people and animals, superbugs flourish and cause infections that are difficult, if not impossible, to treat. Every credible medical and health organization, including the American Medical Association, the U.S. Centers for Disease Control and Prevention (CDC), and the World Health Organization, has said if we don’t significantly reduce antibiotic use in people and livestock, we will soon live in a world where these drugs no longer work!

Lance explains his tracking of resistant bacteria genes to Miles.
Lance explains his tracking of resistant bacteria genes to Miles.

Imagine it: without antibiotics, a bladder infection could go from a painful annoyance to a deadly blood infection; a scraped knee could open the door for an untreatable heart infection; and patients undergoing chemotherapy could lose their chance for survival – not because of the cancer – but because they pick up an untreatable E. coli infection while their defenses are down. We are on the brink of living in a world where this is the new norm, but for some the battle has already been lost.

According to a very conservative estimate by the CDC, each year antibiotic-resistant bacteria account for at least 2 million serious infections, 23,000 deaths, and $20-35 billion in healthcare costs in the U.S. alone. This is not just a U.S. problem, it’s global. A 2015 report from the United Kingdom states that if we don’t make serious efforts to reduce antibiotic use worldwide, by the year 2050 more people will die globally from antibiotic-resistant infections than cancer — some 10 million people every year.

There has been a steady flow of news warning us that antibiotics are becoming increasingly ineffective against deadly bacterial infections. The 2015 discovery of mcr-1, a mobile gene that is resistant to colistin, an antibiotic that has become our last hope for treating people infected with some of the most dangerous superbugs, was alarming. It is believed that this resistant gene originated from agricultural use of colistin. Since its discovery, the gene has spread around much of the globe and closely related genes (mcr-2mcr-3 and mcr-4) have also been discovered in animals and people.

Lance points out several antibiotics to which a colony of bacteria has developed resistance.
Lance points out several antibiotics to which a colony of bacteria has developed resistance.

One recent segment of the PBS NewsHour series highlighted the global need to discover new antibiotics. Unfortunately, the discovery, development and clinical testing of any new drugs is expensive. In order to recoup these costs, companies often focus on expensive medications that people will take throughout their lives, not short-term doses of antibiotics for temporary infections. That’s one reason drug makers developed 13 classes of antibiotics between 1935 and 1968, but only two since then. Even more worrisome, only one out of five drugs that make it to the initial phase of testing in humans will be approved by the U.S. Food and Drug Administration. This underscores the need to protect the antibiotics we have today from overuse and misuse.

It was an important step in 2015 when President Obama launched the National Action Plan for Combating Antibiotic-Resistant Bacteria (CARB), which aims to help doctors, hospitals and patients to cut back on antibiotic overuse. In human medicine, Americans use more antibiotics than most other industrialized nations, with the CDC estimating that 30 percent of these prescriptions are unnecessary. The plan set measurable reduction goals for both inpatient and outpatient settings – 20 percent and 50 percent, respectively – to be achieved by 2020.

Unfortunately, the plan was much weaker on calling for reductions in antibiotic use in animal agriculture, where 70 percent of all antibiotics sold in the U.S. are intended for use. This is disappointing because the most recent data shows that more than 34 million pounds of antibiotics were sold for use in food animals in 2015 compared to approximately 8 million pounds of antibiotics sold in human medicine in 2011 (the most recent data available). Much of this use is to make food animals grow faster or to compensate for overcrowded and dirty living conditions. This breeds drug-resistant bacteria, or superbugs, that can end up in our air and water, in our meat and poultry and, ultimately, in us.

Members of Lance’s lab check bacteria swabbed from store-bought chicken for resistance.
Members of Lance’s lab check bacteria swabbed from store-bought chicken for resistance.

In January 2017, using antibiotics solely for promoting growth in livestock became illegal in the U.S. This is a good step in the right direction, however, the elimination of antibiotics for growth promotion alone will not substantially reduce antibiotic use in food animal production: both the animal pharmaceutical industry and the FDA estimate that growth promotion use accounts for no more than 10% to 15% of all antibiotic sold for use in animals. Furthermore, many of the same antibiotics sold for use as growth promoters are also FDA-approved and labeled for the purpose of disease prevention, including at dosage levels and durations that are similar to or the same as those previously approved for growth promotion. This means that mass administration of medically important antibiotics for long periods will likely continue.

While, the Obama administration took some welcome first steps, it is unclear what the new administration will do to fight antibiotic resistance. So far it has been relatively silent on the issue, though the CARB initiative is still staffed and work continues. Its success depends on funding from Congress. Without it, CARB becomes an unfunded mandate.

On a more positive note, the marketplace is taking a leadership role as large meat and poultry producers and buyers (PerdueTyson FoodsMcDonald’s, and Chick-fil-A, to name a few) in the U.S. have announced commitments to reduce antibiotic use in poultry. However, almost every announcement made so far has centered on reducing antibiotic use in chickens. There are more than 375 million other food animals raised in the U.S. each year — many of which are given antibiotics daily for much of their lives. Farmers, veterinarians, and public health researchers must work together to reduce unnecessary antibiotic use in all animal sectors. Animals must be raised in a way that promotes their health and where antibiotics are used to treat disease rather than being used to compensate for inadequate husbandry.

Just as important, consumers must call for even more change in the marketplace and vote with their wallets by purchasing only from companies that are transparent regarding antibiotic use. And if the change doesn’t happen fast enough, we must continue to urge policymakers to step in with new rules that will ultimately protect public health by reducing the unnecessary use of antibiotics in human medicine and food animal production. We must act quickly as time is running out for preserving the efficacy of our life-saving antibiotics.

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