Urinary Tract Infection (UTI)

UTIs at a glance

  • A urinary tract infection (UTI) is an infection in the lower or upper urinary tract caused by bacteria that enter through the urethra or urine that backs up into the kidneys.
  • Symptoms of a UTI include a strong sense of needing to urinate and pain while urinating.
  • UTIs are generally treated with antibiotics and clear up in one to two days.

What is a UTI?

The urinary tract is made up of the lower tract – the urethra and the bladder – and the upper tract – the kidneys and ureters. Most urinary tract infections start in the lower urinary tract.

Bacteria can enter through the urethra and spread up the lower urinary tract towards the bladder, causing an infection. Bacteria that have infected the bladder may travel up to the ureters to the kidneys and cause a more serious infection.

An upper urinary tract infection, including the kidneys, may cause a severe medical condition.

Many women will experience a UTI at least once in their lives, and some may have more frequent infections. UTIs can be painful and irritating, but most infections are not serious and are easy to treat.


UTIs are diagnosed through a urine sample. Symptoms of UTIs can come quickly and include:

  • A strong, urgent need to urinate
  • Sharp pain or burning in the urethra while urinating
  • Frequent urge to urinate
  • Soreness in the lower abdomen, back, or sides

A change in the urine can also signal a UTI, such as:

  • A strong odor
  • Cloudy appearance

Blood in the urine may be caused by a UTI, but it also may be from other problems. Tell your doctor right away if there is blood in your urine.

If bacteria enters the ureters and spreads to the kidneys, symptoms may include:

  • Fever
  • Chills
  • Back pain
  • Nausea
  • Vomiting

Kidney infections are serious. If you have any of these symptoms, tell your doctor right away.

What causes a UTI?

UTIs can develop for several reasons, most commonly occurring from bacteria entering the urinary tract from the rectum and/or vagina, sex, or from abnormalities in the urinary tract.

Bacteria from the bowel can enter the urinary tract through the urethra causing an infection in the bladder or sometimes in other parts of the urinary tract.

UTIs may also occur after having sex. A woman’s urethra is in front of the vagina and during intercourse, bacteria from the vagina can transfer to the urethra due to close proximity.

Women who change sexual partners or begin having sex more often also tend to experience UTIs. Additionally, using spermicides or a diaphragm can cause UTIs to develop more frequently.

Infections also can occur when urine backs up instead of flowing out of the bladder. This may be caused by:

  • Blockage (a stone) in the kidneys, bladder, or ureters that blocks the flow of urine through the tract.
  • A narrowed or bent tube in the urinary tract.
  • Diverticula – small pockets in the bladder wall that capture urine.
  • Problems with pelvic muscles or nerves.
  • In children – one or both ureters may be abnormally short. This causes urine to back up into the kidneys. As a child grows, the ureters become longer and the problem often goes away.

Other causes

UTIs are more likely to develop in women who:


Urinary tract infections are generally treated with antibiotics. In most cases, treatment is quick, with symptoms disappearing in one to two days.

For severe infections, such as in the kidneys, a hospital stay may be required and intravenous medication may be needed.

Tips to preventing UTIs

  • After a bowel movement or urinating, wipe from front to back.
  • Regularly wash the skin around the rectum and genital areas.
  • Do not use douches, powders, or deodorant sprays on or around the genital area.
  • Drink adequate amounts of fluid, especially water, to flush any bacteria out of the urinary system.
  • Urinate as soon as the need arises.
  • Urinate before and after sex.