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:
Infected kidney stones
Pregnancy -- up to 40% of pregnant women with untreated asymptomatic bacteriuria will develop a kidney infection
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.
Pregnant women, kidney transplant recipients, children with vesicoureteral reflux, and those with infected kidney stones are more likely to be given 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 urinary tract procedure, it should be treated to prevent complications. The course of treatment in these cases depends on the person's risk factors.
Untreated, asymptomatic bacteriuria can lead to a kidney infection in high-risk individuals.
Calling your health care provider
Call your health care provider if the following symptoms occur:
Difficulty emptying your bladder
Flank or back pain
Pain with urination
You will need to be evaluated for a bladder or kidney infection.
Little P, Moore MV, Turner S, et al. Effectiveness of five different approaches in management of urinary tract infection: randomised controlled trial. BMJ. 2010 Feb 5;340.
Gupta K, Hooton TM, Naber KG, et al. International clinicalpractice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011 Mar;52(5):e103-20.
Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010 Mar 1;50(5):625-63.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.