Antibiotic resistance

Antibiotics are medicines that kill bacteria. Antibiotics can be given as pills, ointments, drops or injections. Bacteria can become resistant to antibiotics, which makes it harder to treat infections.


About bacteria

Bacteria are microscopic organisms that are too small to see with the naked eye. We all have lots of bacteria living in our bodies. The human body has both good bacteria (like bacteria that help you digest food and protect you from infection) and bad bacteria (the bacteria that cause diseases).

Bacteria can cause many different infections, like urinary tract infections, pneumonia, blood poisoning, skin infections and diarrhoea. Not all infections will need to be treated with antibiotics, your doctor will prescribe antibiotics only when you need to take them.

About antibiotics

Antibiotics are medicines that kill or stop the growth of bacteria. They are used to treat infections in people, animals and sometimes plants.

Not all antibiotics are active against all types of bacteria. There are more than 15 types of antibiotics. They may be broad spectrum, which means they can kill more than one type of bacteria, or narrow spectrum, meaning they will only kill one type of bacteria.

Bacteria can become resistant to antibiotics and some bacteria are now resistant to many different antibiotics.

How antibiotic-resistant bacteria develop

How antibiotic resistance happens. 1. Lots of germs. A few are drug resistant. 2. Antibiotics kill bacteria causing the illness, as well as good bacteria protecting the body from infection. 3. The drug-resistant bacteria are now allowed to grow and take over. 4. Some bacteria give their drug-resistance to other bacteria, causing more problems.

When bacteria are resistant to antibiotics, it makes it harder to treat infections, and if we can’t treat infections, they can kill. Things like surgery could become very dangerous if we can’t use antibiotics to treat infections.

By using antibiotics carefully, bacteria are less likely to become resistant. That way, antibiotics will still be available when we need them now and in the future.

Antibiotic-resistant bacteria

Bacteria that are resistant to antibiotics are found in the community and in health care settings. Some of the more common antibiotic-resistant infections include:

  • Methicillin Resistant Staphylococcus aureus (MRSA), commonly known as the hospital superbug
  • Extended Spectrum Beta-Lactamase (ESBL)
  • Vancomycin Resistant Enterococci (VRE)

These infections can cause a range of complications.

Who is most at risk?

Anybody can have antibiotic-resistant bacteria in their bodies (carriers) but they may never get sick.

People most at risk of illness due to resistant bacteria are those with lowered immunity such as:

  • hospital patients who are elderly or very sick
  • hospital patients who have an open wound (like a bedsore) or a tube going into their body (like a urinary catheter)
  • people undergoing treatment for cancer.

Patients in hospital may be at risk of getting other infections that can be unrelated to their admission.

Find out more from the Ministry

  • Antimicrobial resistance – information on what we’re doing to monitor and prevent the development of antibiotic-resistant bacteria in New Zealand

The image How Antibiotic Resistance Happens is used courtesy of the Centers for Disease Control and Prevention and Melissa Brower.


We can help stop bacteria becoming resistant and help to stop the spread of resistant bacteria. Find out more at Together we can keep antibiotics working.

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