Urinary tract infection (UTI)

Also known as cystitis or bladder infection

Urinary tract infections are often painful infections of any part of your urinary system – your kidneys, ureters, bladder and urethra.

Lower urinary tract infections (often called a UTI) are very common, especially in women. This includes infections of the bladder (also called cystitis or a bladder infection) or urethra ( the central tube that carries urine out of the body).
  • UTIs are the second most common type of infection.
  • Approximately 50% of women will have at least one UTI in their lifetime.

In rare cases, the infection can spread from the urinary system to the kidneys. This is known as pyelonephritis and needs urgent medical care.

What causes UTI?

The urinary system includes two kidneys, two ureters, a bladder, and a urethra.  It is the body's drainage system for removing wastes and extra water. A range of factors may cause an infection in the urinary system. They include:

  • Bacteria from the anal area making their way into the bladder via the urethra – the urethra is shorter in women so it is easier for bacteria to reach the bladder and cause infection than in men.
  • Bacteria can be introduced when the urethra is pushed on during vaginal sex.
  • Anatomical problems in the kidneys, bladder or tubes.
  • physical irritation of the urethra by chemicals (eg, soaps, perfumes, vaginal hygiene sprays)
  • Ulcers or inflammation near the urethra.
  • Sexually transmitted infection (STI) (e.g. chlamydia).


Who is at risk of developing a UTI?

UTIs can occur at any age and are more common if you:

  • are female (4x more common than in men)
  • have diabetes
  • have a catheter or any tubes in place to drain your bladder
  • have a spinal cord injury.

What are the symptoms of UTI?

Typical symptoms of a urinary tract infection include:

  • pain or burning during or immediately after passing urine
  • fever, tiredness or shakiness
  • an urge to urinate (go to the toilet) more often
  • passing small amounts of urine more frequently
  • pressure in your lower belly
  • urine that smells bad or looks cloudy or reddish
  • repeatedly getting out of bed to pass urine at night.

Pain or ache in the centre back may indicate that the infection has gone up to the kidneys (pyelonephritis).

How is UTI diagnosed?

A UTI is diagnosed by talking about your symptoms and doing a urine test. The urine is tested in the clinic for signs of infection. Sometimes it will be sent away to the lab for further testing and culture.

UTIs in men are unusual and generally need additional investigation, see: urinary problems in men.

If your symptoms go away quickly with the antibiotics, that is all that is needed. If you have recurrent infections, or are at higher risk of complications, then a repeat urine test and culture may be organised a few weeks after treatment to ensure the infection has gone. Your doctor or nurse will advise what is needed for you.

How is UTI treated?

See your doctor or pharmacist if you think you might have a UTI. In most cases, a 3 to 5 day course of antibiotics is needed to treat the infection and reduce the risk of it spreading to the kidneys and causing pyelonephritis.

Many pharmacists are now accredited to sell the antibiotic called trimethoprim to people with uncomplicated UTIs in non-pregnant women aged between 16 to 65 years without a prescription.

If the pain and symptoms do not resolve within 48 hours of starting antibiotics, go back to your doctor or nurse. Sometimes a different antibiotic is needed (if the bacteria is resistant) or further investigations may be recommended.

Any fever, pain in your back or shaking (rigors) needs immediate medical help.

There is no strong evidence that taking products that alkalise your urine (such as Ural®) or drinking cranberry juice improve the symptoms of cystitis.¹,² Likewise, the benefit of traditional advice to drink lots of water to 'flush out the bladder' is questionable — there is no proof that this is helpful. 

Tips to prevent UTIs

  • Drink plenty of water. This helps to dilute your urine and makes you pee more often, which allows the bugs to be flushed from your urinary tract before an infection can begin.
  • Don't delay urinating – avoid 'holding on'.
  • Make sure your bladder is as empty as possible every time you go.
  • Women should always wipe from the front (vagina) to the back (anus) after urinating or having a bowel motion.
  • Urinate before and soon after sexual intercourse.
  • Some earlier studies suggested drinking cranberry juice could reduce recurrent UTIs. A more recent study and review has shown no statistically significant benefit. Read Cranberries for preventing urinary tract infections Cochrane Summaries, 2013.

Learn more

Urinary tract infections Southern Cross Healthcare Group NZ, 2012
Urinary tract infection Ministry of Health NZ, 2013
Cystitis & Urinary tract infections NHS Choices UK


  1. Jepson RG, Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews 2012, Issue 10. 
  2. O'Kane DB, Dave SK, Gore N, et al. Urinary alkalisation for symptomatic uncomplicated urinary tract infection in women. Cochrane Database Syst Rev. 2016 Apr 19;4:CD010745
Credits: Editorial team. Reviewed By: Andreea Dumitru, Senior RN from CCDHB, SIDU - Capital & Coast & Lower Hutt Last reviewed: 31 Oct 2015