Asymptomatic bacteriuria is a condition in which larger than normal numbers of bacteria are present in the urine but symptoms do not result.

Asymptomatic bacteriuria is not normally treated because eradicating the bacteria can be difficult and complications are usually rare. Also, giving antibiotics can alter the balance of bacteria in the body, sometimes allowing bacteria to flourish that are more difficult to eliminate.

Did You Know... Most people who have excess bacteria in the urine and have no symptoms should not be treated.

An exception is if the person has a condition that makes a urinary tract infection particularly risky. Such conditions may include pregnancy, a kidney transplant, taking drugs that suppress the immune system, or having a condition that suppresses the immune system (for example, AIDS, certain cancers, or having a low white blood cell count). For example, cystitis can seriously complicate pregnancy by ascending to the kidneys and causing pyelonephritis, leading to early labor. Also, a urinary tract infection can permanently damage one or both kidneys after a kidney transplant. A urinary tract infection can cause potentially fatal bloodstream infection in people whose immune system is suppressed by a drug or disorder. Sometimes, the immune system becomes suppressed after cancer chemotherapy. Asymptomatic bacteriuria is also sometimes treated in people who have certain kinds of kidney stones that cannot be eliminated and cause repeated urinary tract infections.

Last full review/revision September 2007 by Stewart Shankel, MD