Antibiotic resistance occurs when bacteria adapt or evolve to survive antibiotic treatment. This is a big issue as it can cause antibiotics to become less effective.

Bacteria are single-celled organisms that exist in all environments. Bacteria can exist both inside and outside of other organisms. Some bacteria can cause infections once they enter a person’s body and multiply. There are many different types of bacterial infections that can affect different parts of the body.

If a person has a bacterial infection, a doctor may prescribe antibiotics, which are medications that fight bacterial infections. They do this by either killing the bacteria or making it difficult for it to multiply. While antibiotics can be effective against bacteria, they do not treat other pathogens, such as viruses.

In this article, we will discuss what antibiotic resistance is, how it occurs, and strategies to prevent it.

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In some situations, infectious bacteria can adapt or mutate in response to the use of antibiotics. This can cause the bacteria to no longer respond to the antibiotics. As such, certain antibiotics may no longer be effective at treating certain strains of bacteria.

The resistant strain of bacteria may then multiply and spread to other people. These individuals may then use antibiotics to treat their infection. However, the strain’s antibiotic resistance will cause the treatment to be less effective or fail. As such, bacterial infections may not resolve and people can experience severe complications.

There are many possible adaptations or mutations that can occur within bacteria to help them resist antibiotics. These may include:

  • Restricting the access of the antibiotic: Bacteria may adapt to change the entryways or limit the number of entryways that the antibiotic can use to enter the bacteria. This can include using outer membranes to prevent antibiotic medications from entering.
  • Removing the antibiotic: Some bacteria may use pumps in the cell walls to remove antibiotic drugs that enter the cell.
  • Changing or destroying the antibiotic: Some bacteria can use enzymes or proteins to break down the antibiotic. This can change or destroy it, making it no longer effective.
  • Changing the antibiotic’s targets: Many antibiotics single out and destroy specific parts of certain bacteria, known as targets. Some bacteria can adapt to change the antibiotic’s target, so the drug can no longer work.
  • Bypassing the antibiotic’s effects: Some bacteria can develop new cell processes. This can help the bacteria avoid using the antibiotic’s target, making the drug no longer effective.

Bacteria that do survive antibiotic use will have resistance traits in their DNA that they can pass on when they multiply. They may also pass on these traits to other bacteria. When a person requires antibiotics as a treatment, the health benefits usually outweigh the risk of antibiotic resistance.

However, people are taking antibiotics too often when they should not. When people misuse antibiotics, they can threaten the usefulness of these medications. The Centers for Disease Control and Prevention (CDC) estimates that medical professionals in the United States are prescribing around 47 million antibiotic treatments for infections that do not require antibiotics.

Antibiotic resistance can cause antibiotic drugs to become less effective. This can make bacterial infections of antibiotic-resistant bacteria difficult to treat. In some people, they may be impossible to treat. If a person has an infection with antibiotic-resistant bacteria, they may require costly and sometimes toxic alternative treatments.

Other complications of antibiotic resistance can include:

  • longer hospital stays for people with bacterial infections
  • higher medical costs
  • an increased mortality rate for people with bacterial infections

Medical professionals have recorded antibiotic resistance associated with almost all antibiotics. Certain bacterial infections cause big threats due to the severity of the infection and how common they are.

Below are some of the bacteria that are causing the biggest threats due to antibiotic resistance:


Enterobacteriaceae is a family of bacteria that can cause serious infections of the:

These bacteria can also cause pneumonia. Some of these bacteria have developed resistance to almost all available antibiotics, making these infections difficult to treat.

Neisseria gonorrhoeae (N. gonorrhoeae)

N. gonorrhoeae is a species of bacteria that causes the sexually transmitted infection (STI), gonorrhea. Not all of these infections are drug-resistant, but N. gonorrhoeae has developed resistance to nearly all of the antibiotics that doctors use to treat the infection.


Acinetobacter is a group of bacteria that is commonly present in soil and water. This group of bacteria can cause infections in a person’s:

  • blood
  • urinary tract
  • lungs
  • wounds

Infections with Acinetobacter commonly occur in patients in healthcare settings and intensive care units. These infections commonly affect people:

  • with weakened immune systems
  • with chronic lung disease
  • with open wounds
  • on breathing machines or catheters

Antibiotic resistance means that at least three different classes of antibiotics can no longer cure Acinetobacter infections.

Pseudomonas aeruginosa (P. aeruginosa)

P. aeruginosa bacteria can cause mild illnesses, such as ear infections and skin rashes. However, if a person has a weakened immune system, they may develop severe infections in their bloodstream or contract pneumonia.

This can occur in people in hospitals with wounds from surgery or who are using breathing machines or catheters. Some strains of P. aeruginosa are resistant to most or all antibiotics. This makes these infections dangerous and hard to treat.


Salmonella is a type of bacteria that can cause:

Some strains of Salmonella are resistant to antibiotics, which can cause infections to become more severe. More severe Salmonella infections can spread to a person’s bloodstream and may become life threatening.

The following factors contribute to antibiotic resistance:

  • the misuse of antibiotics
  • overuse of antibiotics
  • poor infection prevention and control

There are a number of things individuals can do to help prevent and control antibiotic resistance, including:

  • only using antibiotics that a certified healthcare professional prescribes to them
  • never demanding antibiotics if a healthcare professional says they do not need them
  • always following a health worker’s advice when using antibiotics, including taking them for the entire prescribed length
  • avoiding sharing or using leftover antibiotics
  • regularly washing hands
  • preparing food hygienically
  • avoiding close contact with people who are unwell
  • practicing safe sex
  • keeping vaccinations up-to-date

Antibiotics are drugs people take to treat bacterial infections. Some bacteria can adapt or mutate to survive antibiotic treatment. These bacteria can then multiply and pass on their antibiotic resistance to newly formed cells.

Bacterial infections with antibiotic-resistant bacteria can be hard to treat. These infections can also pass from person to person and antibiotic resistance will spread. A person can take steps to help prevent and control antibiotic resistance by only using antibiotics when a doctor prescribes them and always following a healthcare provider’s advice when using them.