Antibiotics and Antimicrobial Resistance: The Basics

Antibiotics are drugs that kill certain germs — bacteria — or stop them from growing. They are critical for preventing and treating bacterial infections in people, animals and crops, and in health care they are among the most powerful tools against life-threatening infections such as sepsis, the body's extreme response to infection. But every use of an antibiotic can cause side effects and add to antimicrobial resistance, so they should be used only when they are needed.

Drug-resistant nontyphoidal Salmonella bacteria, in a medical illustration. CDC.

Bacteria and viruses

Bacteria live inside and outside our bodies. Most are harmless and some are helpful, but some cause infections such as strep throat and urinary tract infections.

Viruses are different germs. They cause infections such as colds and flu — and antibiotics do not treat them.

Using antibiotics well

• Unnecessary use means taking antibiotics you don't need: for colds and flu, or for infections that are sometimes bacterial but often don't need antibiotics, such as many sinus infections and some ear infections.
• Misuse means taking the wrong antibiotic, the wrong dose, or taking it for the wrong length of time.

Talk with your doctor about the best treatment, and about how to feel better when you don't need an antibiotic. Never pressure your doctor for a prescription, and don't save antibiotics for later.

Antimicrobial resistance

Antimicrobial resistance happens when germs such as bacteria and fungi develop the ability to defeat the drugs designed to kill them, so they keep growing. It is the germs that become resistant, not your body.

• Resistant infections can be hard, and sometimes impossible, to treat. They often mean longer hospital stays, more follow-up visits, and costly, toxic alternative treatments.
• A germ doesn't have to resist every drug to be dangerous; resistance to even one antibiotic can cause serious problems.
• Anyone can be affected at any age, but people receiving health care and people with weakened immune systems are often at higher risk.
• Resistance affects veterinary medicine and agriculture as well as human health.

Much of modern medicine depends on being able to fight infection with antibiotics — joint replacements, organ transplants, cancer therapy, and care for chronic diseases such as diabetes, asthma and rheumatoid arthritis. If antibiotics and antifungals stop working, we lose the ability to treat those infections. Using antibiotics appropriately helps keep these lifesaving drugs working for the future.

What you can do

Everyone has a part to play. Taking antibiotics only when they are needed, and exactly as prescribed, protects you and your family and helps slow resistance. CDC tracks the problem in reports such as Antibiotic Resistance Threats in the United States, 2019 and its antibiotic stewardship reports.

Sources

• Centers for Disease Control and Prevention: "Antibiotic Use and Antimicrobial Resistance Facts."