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).
Urinary tract infections are often painful infections of any part of your urinary system – your kidneys, ureters, bladder and urethra.
- 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
- 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.
Urinary tract infections Southern Cross Healthcare Group NZ, 2012
Urinary tract infection Ministry of Health NZ, 2013
Cystitis & Urinary tract infections NHS Choices UK
Resources for health professionals
This section contains detailed information and resources of more interest to health professionals.
Clinical pathways & guidelines for urinary tract infections
Clinical management of urinary tract infections
There are two types of urinary tract infection
- uncomplicated - very common, affect 50% women at least once in their lifetime.
- complicated - most other groups eg men, children, pregnancy, underlying kidney disease etc.
Women presenting with classic symptoms and a normal genitourinary (GU) tract:
- dysuria, frequency, urgency
- most frequent in young sexually active women.
First line treatment for symptomatic women is to start with either trimethoprim or nitrofurantoin. Norfloxacin should only be used if the the initial treatment with trimethoprim or nitrofurantoin fails, and laboratory culture and sensitivity data supports use of norfloxacin.
Urine testing – dip stick only.
Urine culture – not needed unless poor response to antibiotics, then moves to complicated group.
All UTIs in the following groups are considered complicated:
- pregnant women
- when pyelonephritis is suspected
- failed antibiotic treatment or recurrent UTI
- catheter in-situ and symptoms of UTI
- hospital-acquired infection
- abnormal genitourinary tract/recent instrumentation
- renal impairment.
Who to treat
(The following section is based on information from Best Practice Antibiotics Guide 2013)
- Antibiotic treatment is indicated for all people who are symptomatic.
- Asymptomatic bacteria requires antibiotic treatment in women who are pregnant but not in elderly women or patients with long-term indwelling urinary catheters.
Trimethoprim Adult: 300 mg, once daily, for three days (avoid during the first trimester of pregnancy).
Nitrofurantoin Adult: 50 mg, four times daily, for five days (avoid at 36+ weeks in pregnancy, and in significant renal impairment).
Treat for seven days in pregnant women and in males
Norfloxacin Adult: 400 mg, twice daily for three days (should be reserved for isolates resistant to initial empiric choices and avoided during pregnancy).
Who needs urine culture?
- Non-pregnant females with uncomplicated UTI do not require a urine culture.
- Urine culture is needed in males, women who are pregnant, and those who fail to respond to empiric treatment within two days.
- Women who are pregnant should have repeat urine culture one to two weeks after completing treatment to ensure cure.
UTI management in children
Guideline: Urinary tract infection Starship Clinical Guidelines (NZ), 2012
(Refer to the guideline and articles in Best Practice Journal 2013 and the Antibiotics Guide July 2013 for the details. A summary is provided below)
Refer to hospital:
- infants aged under three months
- those with severe illness
- those with recurrent infection
- consider referral of children aged under six months.
Treatment by GP or Nurse:
- Children aged over six months, without renal tract abnormalities, and who do not have acute pyelonephritis, may be treated with a short course (three days) of antibiotics.
All children with suspected UTI should have a urine culture collected as a clean specimen (clean catch, catheter, midstream urine) as it may be a marker for previously undetected renal malformations, particularly in younger children. In older children it can be a marker for bladder and/or bowel dysfunction.
See: Managing urinary tract infections in children BPJ 44 May, 2012.
Escherichia coli, Proteus spp., Klebsiella spp., Enterococcus spp.
Trimethoprim + sulfamethoxazole Child: 0.5 mL/kg/dose oral liquid (40+200 mg/ 5 mL), twice daily, for three days (maximum 20 mL/dose)
If a child can swallow tablets, co-trimoxazole 80+400 mg tablets can be used (one tablet is equivalent to 10 mL of co-trimoxazole oral liquid). Read more about Trimethoprim + sulfamethoxazole NZ Formulary ( Deprim liquid & Trisul tablets)
Cefaclor Child: 8 – 10 mg/kg/dose, three times daily, for three days (maximum 500 mg/dose)
Amoxicillin clavulanate Child: 10 mg/kg/dose (amoxicillin component), three times daily, for three days (maximum 500 mg/dose,amoxicillin component)
- Quinolone antibiotics - limit use Best Practice Journal, April 2011
- Antibiotics Guide – UTI section Best Practice Journal, July 2013
- Amoxicillin clavulanate in UTI BPJ 55, October, 2013
- Urinary tract infection Starship Clinical Guidelines (NZ), 2012