Definition of Urinary tract infection - adults:

A urinary tract infection, or UTI, is an infection that can happen anywhere along the urinary tract. The urinary tract includes the:

• Bladder
• Kidneys
• Ureters -- the tubes that take urine from each kidney to the bladder
• Urethra -- the tube that empties urine from the bladder to the outside

See also:

• Cystitis - acute
• Cystitis - recurrent
• Cystitis - noninfectious
• Interstitial cystitis
• Kidney infection (pyelonephritis)
• Urinary tract infection - children

Causes, incidence, and risk factors:

Urinary tract infections (UTIs) have different names, depending on where the infection is located.

Cystits, a common condition, is an infection of the bladder. It is usually caused by bacteria entering the urethra and then the bladder. This leads to inflammation and infection in the lower urinary tract.

Pyelonephritis is an infection of one or both kidneys and the surrounding area.

Certain people are more likely to get UTIs. Women tend to get them more often because their urethra is shorter and closer to the anus. Persons with diabetes and very old adults (especially those in nursing homes) are more likely to develop UTIs. The elderly are at increased risk for such infections because the bladder doesn't empty fully due to certain prostate and bladder conditions.

Children can also develop UTIs.

The following increase your chances of developing a UTI:

• Bowel incontinence
• Having a tube called a catheter inserted into your urinary tract
• Kidney stones
• Staying still (immobile) for a long period of time (for example, while you are recovering from a hip fracture)
• Menopause
• Narrowed urethra
• Not drinking enough fluids
• Pregnancy
• Prostate inflammation or enlargement
• Sexual intercourse, especially if you have multiple partners
• Using a diaphragm for birth control