Antibiotic resistance

Antibiotic resistance – when bacteria change so antibiotics no longer work to treat infections – is one of the most serious global health threats.

Key points:

  1. Misuse and overuse of antibiotics has resulted in high proportions of bacteria that cause common infections (ie, urinary tract infections, pneumonia, bloodstream infections) now being antibiotic resistant.
  2. The failure of these 'first line' antibiotics means we have to use less conventional medications, many of which are more costly and associated with more serious side effects.
  3. There is also the risk that infections which have for many years been easily managed may once again become untreatable and uncontrollable.
  4. Preventing infection and appropriate use of antibiotics are two key ways of fighting antibiotic resistance.


The single most important factor leading to antibiotic resistance is the mis- and over-use of antibiotics. 

  • Antibiotics are among the most commonly prescribed drugs used in human medicine.
  • Up to 50% of all the antibiotics prescribed for people are not needed or not prescribed effectively.
  • Antibiotics are also routinely used in food animals to prevent, control and treat disease and to promote growth.

How antibiotic resistance happens

Antibiotic resistance occurs as part of a natural process in which bacteria evolve.

  • When you are sick and are prescribed antibiotics there are lots of bugs (bacteria) living in your gut and a few are drug resistant.
  • Antibiotics kills the bacteria that causes the illness as well as the healthy bacteria protecting you from disease.
  • The drug-resistant bacteria are now able to grow and out number the other bacteria that are there.



The growth of antibiotic resistance is also influenced by the spread of resistant strains of bacteria from:

  • person to person
  • non-human sources in the environment, including food.


Key ways you can help combat antibiotic resistance are avoiding infections and using antibiotics correctly.

Avoiding infection in the first place:

  • reduces the amount of antibiotics that have to be used globally
  • reduces the likelihood that resistance will develop during therapy
  • prevents the spread of resistant bacteria.

Infections can be avoided by:

  • immunisation
  • safe food preparation
  • handwashing.

Appropriate use of antibiotics:

  • using antibiotics only when prescribed by a doctor
  • completing the full prescription, even if they feel better
  • never sharing antibiotics with others or using leftover prescriptions.

Consequences of inappropriate antibiotic use:

  • Using antibiotics to treat viruses. Antibiotics are effective against bacterial infections. Antibiotics don't work against viruses.
  • Taking an antibiotic when you have a viral infection, won't make you feel better, can contribute to antibiotic resistance.
  • Not taking antibiotics the full course of antibiotics, the antibiotic may wipe out some, but not all, of the bacteria, the surviving bacteria become more resistant and can be spread to other people.

When bacteria become resistant to first line treatments:

  • the risk of complications and death is increased
  • doctors have to resort to less conventional medications
  • these are more costly and associated with more-serious side effects.


Antibiotic Resistance Threats in the United States Centers for Disease Control and Prevention, 2013
Antibiotics misuse puts you and others at risk. Mayo Health Clinic, 2012
Antimicrobial resistance: global report on surveillance 2014 World Health Organization, 2014
Upfront: Is in the cupboard bare? The threat of antimicrobial resistance BPAC, June 2013


Credits: Health Navigator team. Reviewed By: Editorial team Last reviewed: 15 Mar 2015