Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Asymptomatic Bacteriuria

What Is It?

When a significant number of bacteria show up in the urine, this is called "bacteriuria." Finding bacteria in the urine can mean there is an infection somewhere in the urinary tract. The urinary tract is the system that includes:

• The kidneys, which make urine

• The ureters – thin tubes connecting the kidneys to the bladder

• The bladder, where urine can be stored

• The urethra – the final pathway to move urine from the bladder to outside the body.

In asymptomatic bacteriuria, large numbers of bacteria are present in the urine. However, the person has no symptoms of a urinary tract infection (asymptomatic means without symptoms). It is not clear why the bacteria don't cause symptoms. It may be that asymptomatic bacteriuria is caused by weaker (less "virulent") bacteria. The condition does not always need to be treated.

Asymptomatic bacteriuria is most common in:

• Elderly women

• People with diabetes

• People with bladder catheters.