Since the 1940s, antibiotics have saved millions of lives and played a critical role in protecting public health. However, many of the antibiotics we rely on to cure disease in humans are also used on concentrated animal feeding operations (CAFOs), or factory farms, to prevent disease in overcrowded conditions. This dangerous misuse of antibiotics in agriculture is partially responsible for the emergence of drug-resistant bacteria that pose a grave threat to public health.

Scientists, public health advocates, and consumers are pushing to end the inappropriate use of medically important antibiotics in livestock production, and while antibiotic use has recently declined in the United States, dangerous misuse is still a serious problem.

Antibiotics and Antibiotic-Resistance

Bacteria are everywhere and are vital to the proper functioning of our bodies. In fact, humans have roughly an equal number of bacteria to human cells. However, while most of the bacteria on and in our bodies actually help keep us healthy, some cause serious illnesses and death.

Since the discovery of the first antibiotic, penicillin, in the early twentieth century antibiotics have been used to cure a wide range of bacterial diseases including Lyme disease, syphilis, tuberculosis and a wide range of other infections. Antibiotics, such as penicillin, tetracycline and amoxicillin kill or inhibit the growth of bacteria without causing significant harm to people.

Misuse of antibiotics, however, leads to the evolution of antibiotic-resistant bacteria. When bacteria are continually exposed to low doses of an antibiotic, those resistant to the drug survive and reproduce while the rest die off, resulting in a new bacteria population that resists the antibiotic. Antibiotic misuse in human medicine — such as the prescription of antibiotics to treat conditions caused by viruses like the cold or flu (which cannot be treated this way) and patients’ failure to complete their antibiotic regimen — is widely understood as a common cause of resistance. Another source of resistance, the overuse of antibiotics in agriculture, is less well-known, but poses a serious threat.

When antibiotic-resistant bacteria become widespread, life-saving antibiotics become ineffective, forcing researchers and drug companies to constantly develop new drugs. However, in recent years, new antibiotic discovery has slowed while antibiotic resistance becomes more common.

As a result, infections from resistant bacteria are both increasingly common and more difficult to treat. The Centers for Disease Control (CDC) estimates that each year in the US, at least 2.8 million people acquire antibiotic-resistant bacterial infections and 35,000 people die as a direct result. Health care costs associated with antibiotic-resistant bacteria amount to about $20 billion each year in the US alone and amount to more than eight million extra patient days in the hospital. A 2014 study by the Review of Antimicrobial Resistance, convened by the UK Prime Minister, estimates that by 2050, if nothing is done to curb antibiotic misuse, resistant bacteria will kill 10 million people a year — more than are killed by cancer today — and will cost the global economy $60 trillion to $100 trillion.

Dr. Margaret Chan, the Director-General of the World Health Organization (WHO), released a statement on World Health Day 2011 about the bleak future for treating bacterial infections if no steps are taken to slow the development of antibiotic-resistant bacterial strains. She warned: “[I]n the absence of urgent corrective and protective actions, the world is heading toward a post-antibiotic era, in which many common infections will no longer have a cure and, once again, kill unabated.” WHO released the first-ever report on global antibiotic resistance in 2014, outlining the serious threat antibiotic-resistant bacteria present to public health around the world.

Antibiotics and the Animal Industry

While antibiotic misuse in medicine is subject to serious public scrutiny, antibiotic abuse in agriculture is both more widespread and subject to far less oversight. According to the FDA, more than 20 million pounds of medically important antibiotic drugs were sold for use on livestock farms in 2014 — about 80 percent of all antibiotics sold.