Antibiotics are vital for healthcare. They’ve saved countless lives since they were introduced about 80 years ago. But some bacterial infections have since developed resistance to antibiotics.

Antibiotic resistance means that a specific bacterial strain can’t be treated by a specific antibiotic. The Centers for Disease Control and Prevention (CDC) estimates that about 2.8 million people develop antibiotic-resistant infections each year, resulting in more than 35,000 deaths.

Antibiotics are toxic to certain types of bacteria and are able to stop bacteria from functioning normally. This causes bacteria to either die or to be unable to multiply. When bacteria die off or stop multiplying, it’s much easier for your immune system to fight off infection.

Some types of antibiotics are effective against a wide range of bacteria. These are called broad-spectrum antibiotics. For example, amoxicillin is a common broad premium antibiotic that’s prescribed for a variety of bacterial infections.

Other antibiotics only work on a few types of bacteria. These are known as narrow-spectrum antibiotics. Penicillin is a commonly known example of a narrow-spectrum antibiotic.

Bacteria are living organisms. They can change and evolve to protect themselves from antibiotics. Resistance happens when bacteria come in contact with antibiotics and survive.

Mutations in their genes allow some bacteria to survive these antibiotics, and they pass these genes along to their descendants. This is how antibiotic-resistant strains of bacteria are formed.

Bacteria can develop several different defense mechanisms against antibiotics. For instance, gene mutations can allow bacteria to:

  • Ignore the antibiotic
  • Block the antibiotic
  • Get rid of the antibiotic
  • Change the action of the antibiotic
  • Destroy the antibiotic
  • Make the antibiotic attack a different target

Antibiotics have been in widespread use for the past several decades. This means that many bacterial infections have been exposed to multiple antibiotics. This exposure had led to antibiotic strains of several common bacterial infections. These strains are especially common in hospitals and other environments that treat or are exposed to large numbers of people with bacterial infections.

How long does it take for bacteria to become resistant?

Different types and strains of bacteria behave differently. And the exact antibiotic affects how long antibiotic resistance takes. But some studies have shown that bacteria can begin to develop antibiotic resistance as early as 11 days.

How did MRSA become resistant to antibiotics?

Methicillin-resistant Staphylococcus aureus (MRSA) is an infection with staphylococcus bacteria, commonly known as a staph infection, that can’t be treated with many common antibiotics. MRSA was first reported in 1960, only a year after the antibiotic methicillin was introduced. But MRSA infections rose sharply in the early 2000s.

There are two types of MRSA infections. Those gotten in a hospital, and those gotten elsewhere in the community. Because this bacteria is especially contagious and hard to kill, it has become endemic to many hospitals and other healthcare facilities. This is likely what drove the genetic mutations that make MRSA so resistant to antibiotics.

The CDC and other organizations are tracking both types of MRSA infections as well as responses to treatments. This data will help control and possibly prevent the spread of MRSA in the future.

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Although antibiotic resistance refers to bacteria and to your body, there are still steps you can take to avoid contributing to it. One of the most important things you can do is to remember that not every infection needs to be treated with antibiotics. For example, infections such as the flu and colds are caused by viruses, not bacteria, and you shouldn’t take an antibiotic for them.

Other steps you can take include:

  • Only take antibiotics when it’s really necessary, as prescribed by a doctor or healthcare professional
  • Don’t take leftover antibiotics from an old prescription
  • Don’t take an antibiotic that was prescribed to someone else
  • Take your antibiotic for exactly as long as prescribed, even if you feel better
  • Practice good handwashing habits by washing your hands often with soap and warm water
  • Stay home when you’re feeling sick
  • Prepare and cook food on clean surfaces
  • Always cook meats fully and avoid raw dairy products
  • Talk with a doctor about vaccinations and boosters

Major healthcare organizations in the United States and around the world are taking steps to overcome antibiotic resistance. These efforts will work to combat the problem from multiple angles and include:

  • Finding alternate medications to treat some bacterial infections
  • Developing new antibiotics
  • Pairing medications together to combat resistance
  • Limiting the bacterial infections that are treated with infections
  • Lowering the number of days or doses of antibiotic use during infection treatment
  • Educating the public about antibiotic resistance

Healthline will continue to report on new treatments for antibiotic resistance as they develop.

Antibiotics are used to treat bacterial infections. They block the way bacteria function and cause bacteria to die or to stop multiplying. But because bacteria are living organisms, bacteria can adapt over time and can develop genetic changes that allow them to resist antibiotics. When this happens, an antibiotic that was previously able to treat a certain bacterial infection will no longer be effective against it. Bacteria can spread these genetic changes to other bacteria as they multiply. This allows antibiotic-resistant strains of bacteria to develop.

Overuse of antibiotics leads to greater resistance against them. This is why it’s important to only take antibiotics when you really need them. Other steps you can take include always taking antibiotics exactly as prescribed and taking steps to keep yourself healthy, such as practicing good hand washing and getting vaccinated.