A urinary-tract infection occurs when bacteria contaminate any part of the normally sterile system of organs and tubes that process, store and move urine through and out of the body. The urinary tract includes the kidneys, ureters, bladder and urethra.
The most common types of urinary-tract infection are cystitis, which is an infection in the bladder, and urethritis, which is an infection in the urethra. Kidney infections, called pyelonephritis, are more rare and far more serious.
Infection-causing bacteria, especially E. coli bacteria, most commonly come from the gastrointestinal tract. Urinary-tract infections cannot be transmitted from one person to another.
Urinary-tract infections are among the most common causes of visits to a doctor’s office, particularly for women. Approximately half of women will have at least one urinary-tract infection in their lifetime. Women are nine times more likely to get urinary-tract infections than men.
A woman’s anatomy makes her vulnerable to bacteria moving from around the anus into the urinary tract. This is simply because her urethra—the tube that carries urine from the bladder out of the body—is shorter than a man’s. Sexual intercourse, the use of a diaphragm and failing to wipe from front to back after urinating or defecating add to this anatomical vulnerability.
Other anatomical problems can cause some women to be more prone to infections and to get them repetitively. These problems include kidney stones, tumors and atrophy of the urinary tract (caused by a decrease in estrogen).
A urinalysis determines if there is an infection, and the results are available quickly.
A urine culture involves trying to grow the bacteria in a dish to see what the organism is. This information helps the doctor decide what antibiotics are appropriate to treat the infection.
A person with recurrent urinary-tract infections will require a more involved workup. This may include a cystoscopy, in which a small tube-shaped camera is inserted through the urethra to view the bladder for details that are difficult to see with an X-ray. The test is not painful and lasts approximately 5 minutes. Diagnosis may also require some form of imaging of the upper urinary tract. These extra steps help the doctor determine if you have an anatomical or other problem that predisposes you to repetitive infections.
Antibiotics are the mainstay of treatment. They can begin right after a urinalysis, although the doctor might change the antibiotic after reviewing the results of the urine culture. Your medical history also will affect the doctor’s choice of an antibiotic.
If you have recurrent urinary-tract infections, treatment is more involved. First, the doctor will treat the existing infection and minimize recurrence. Then the doctor will try to identify and treat the underlying cause of the infections.