Asymptomatic bacteriuria

Asymptomatic bacteriuria is a significant number of bacteria in the urine that occurs without usual symptoms such as burning during urination or frequent urination.

Asymptomatic bacteriuria may not need treatment, which makes it different from a bacterial urinary tract infection.

Causes, incidence, and risk factors

Asymptomatic bacteriuria occurs in a small number of healthy individuals. It more often affects women than men. The reasons for the lack of symptoms are not well understood.

Most patients with asymptomatic bacteriuria do not need treatment because the bacteria are not causing any harm. Persons who have urinary catheters often will have bacteriuria, but most will not have symptoms.

Certain people are at a higher risk for kidney infections if they develop asymptomatic bacteriuria. The following increases your risk:

• Diabetes
• Infected kidney stones
• Kidney transplant
• Older age
• Pregnancy -- up to 40% of pregnant women with untreated asymptomatic bacteriuria will develop a kidney infection
• Vesicoureteral reflux in young children

Symptoms

By definition, asymptomatic bacteriuria causes no symptoms. The symptoms of a urinary tract infection include burning during urination, an increased urgency to urinate, and increased frequency of urination.

Signs and tests

Asymptomatic bacteriuria is detected by the discovery of significant bacterial growth in a urine culture taken from a urine sample.

Treatment

Not all patients with asymptomatic bacteriuria need treatment. Pregnant women, kidney transplant recipients, children with vesicoureteral reflux, and those with infected kidney stones appear to be more likely to benefit from treatment with antibiotics.

Giving antibiotics to persons who have long-term urinary catheters in place may cause additional problems. The bacteria may be more difficult to treat and the patients may develop a yeast infection.

If asymptomatic bacteriuria is found before a urological procedure, it should be treated to prevent complications. The course of treatment in these cases depends on the person's risk factors.

Complications

Untreated, asymptomatic bacteriuria can lead to a kidney infection in high-risk individuals. In some cases, particularly in those who have had kidney transplants, such infections may lead to the loss of kidney function.