(See also Overview of Urinary Tract Infections.)
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 common in certain groups of people, such as those who have bladder catheters inserted for an extended period. 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.
An exception is if the person has a condition that makes a urinary tract infection particularly risky. Such conditions may include
A transplanted kidney
Taking drugs that suppress the immune system
Having a condition that suppresses the immune system (for example, AIDS, certain cancers, or having a low white blood cell count)
Young children with severe backflow (reflux) of urine from the bladder into the ureters
Before certain invasive procedures that can cause bleeding in the urinary tract (eg, transurethral resection of the prostate)
For example, a bladder infection (cystitis) can seriously complicate pregnancy by ascending to the kidneys and causing a kidney infection (pyelonephritis), leading to early labor. Also, a urinary tract infection can damage a transplanted kidney. 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 thus cause repeated urinary tract infections) and in people scheduled to have a urinary tract surgical procedure done.
Because asymptomatic bacteriuria is not usually treated, doctors do not usually do tests to identify it unless the person has a condition that warrants such treatment. Bacteriuria can be confirmed by a urine culture, in which bacteria from a urine sample are grown in a laboratory to identify the numbers and type of bacteria. When treatment is warranted, antibiotic therapy is given.