Antibiotic Resistance Is Beefing Up

Antibiotic Resistance Is Beefing Up

Since their advent, antibiotics have revolutionized medicine and saved countless lives. However, the overuse of antibiotics, particularly in cattle, is causing the rise of global antibiotic resistance.


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Biology, Genetics, Health

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Anyone who has gone to the doctor for a bacterial infection, such as strep throat (Streptococcal pharyngitis), is likely familiar with antibiotics. The doctor typically prescribes an antibiotic to kill the bacteria and advises patients to take the full course of antibiotics, even if they start to feel better. This is to protect against antibiotic resistance, which is when an antibiotic no longer kills bacteria it used to control.

However, prescriptions are not the only source of concern for antibiotic resistance. Over 70 percent of antibiotics sold in the United States are given to livestock, including cattle, which translates to significant human health effects.

Revolutionary Treatments, Now at Risk

For much of human history, bacteria have presented a danger to human health, with bacterial diseases like the bubonic plague wiping out large parts of the world's population. Fortunately, the development of antibiotics has revolutionized treatments for such bacterial diseases, which means they have not been able to spread as they once did. However, this safety is being put at risk by the increasing regularity of antibiotic resistance.

Like other organisms, bacterial populations adapt and evolve over time. When bacteria are exposed to an antibiotic over a long period of time, they can evolve a resistance to the drug. Initially, bacteria treated with antibiotics will die. However, if some bacteria happen to have a genetic mutation, or DNA change, that makes them resistant to the antibiotics, those bacteria will continue to survive and multiply.

Some bacteria have already developed resistance to antibiotics. Notably the bacteria that cause staph infections, methicillin-resistant Staphylococcus aureus, are highly resistant to antibiotics.

Farm Animals and Antibiotics

Antibiotics are given to farm animals for some of the same reasons they are given to humans. Livestock are often housed together in close quarters, where there is increased risk for spreading disease. Cattle in particular are also at risk for infections because they are often fed a corn-based diet despite having evolved to eat grass. Unlike with human medicine, however, antibiotics are often fed to cattle as a preventative measure, rather than as a treatment.

Antibiotics have another unexpected benefit: They allow livestock to grow larger much more quickly than usual. This has led many cattle producers to feed livestock low doses of antibiotics for long time periods in order to gain a greater profit from a single animal, while also contributing to antibiotic resistance.

Contaminated Meat, Milk, and Fertilizer

Antibiotic resistance in cattle impacts people as well. Many of the antibiotics given to cattle are also used in human medicine. Eating meat or consuming milk from an animal with antibiotic-resistant bacteria may infect a human with that resistant bacteria. The most common bacteria that cause food-borne illness are Salmonella and Campylobacter. They too are resistant to antibiotics. Some forms of salmonella can be passed from cattle to humans by people eating meat or dairy products.

Antibiotic-resistant bacteria can also make their way into the air, water, and soil. For example, manure from cattle is often used to grow vegetables. If this manure contains antibiotic-resistant bacteria, it can contaminate vegetables and soil.

The increased use of antibiotics also has negative effects on the human microbiome, the bacteria in the gut that keep us healthy. This can result in short-term infections, in which the absence of good bacteria allows bad bacteria to thrive. Changes to the microbiome can also mean long-term health consequences, such as an impaired immune system.

Government Action, Consumer Caution

The dangers of antibiotic resistance are recognized all over the world. Governments are responsible for establishing guidelines for antibiotic use in livestock. Partnerships between governments, cattle producers, and veterinarians are aimed at reducing the overall use of antibiotics. This means only using antibiotics prescribed by a veterinarian and not using antibiotics to improve production. Improving livestock care could also help reduce the spread of disease and thus the need for antibiotics.

Individual actions can also help prevent the spread of antibiotic resistance. For instance, lowering how much meat you eat reduces the risk for infection. Consumers can also look for meat labeled as "antibiotic free." It is also recommended to use safe cooking methods, such as cooking to the appropriate temperature, separating meats and vegetables, and washing your hands.

Halting antibiotic resistance demands a collaborative effort to adjust our approach to the medicine we take and the food we eat. However, like the initial discovery of antibiotics, the effort to stop antibiotic resistance will transform human and animal health alike.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Tyson Brown, National Geographic Society
National Geographic Society
Production Managers
Gina Borgia, National Geographic Society
Jeanna Sullivan, National Geographic Society
Program Specialists
Sarah Appleton, National Geographic Society, National Geographic Society
Margot Willis, National Geographic Society
Last Updated

October 19, 2023

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