Asymptomatic Bacteriuria

How to Cite This Chapter: Mertz D, Duława J, Drabczyk R. Asymptomatic Bacteriuria. McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. Accessed June 18, 2024.
Last Updated: October 14, 2021
Last Reviewed: October 14, 2021
Chapter Information


Asymptomatic bacteriuria (ABU) is diagnosed when significant bacteriuria (≥105 colony-forming units [CFU]/mL of ≥1 strain) is detected in properly collected urine samples (midstream specimens or catheter samples) and is not accompanied by clinical signs or symptoms of urinary tract infection. Two consecutive cultures, preferably at an interval of ≤2 weeks, are required to diagnose asymptomatic bacteriuria based on a midstream specimen in women. Except for certain cases (see Treatment, below), ABU must not be treated with antibiotics, as the potential harm outweighs the potential benefits.Evidence 1Strong recommendation (downsides clearly outweigh benefits; right action for all or almost all patients). High Quality of Evidence (high confidence that we know true effects of the intervention). Zalmanovici Trestioreanu A, Lador A, Sauerbrun-Cutler MT, Leibovici L. Antibiotics for asymptomatic bacteriuria. Cochrane Database Syst Rev. 2015 Apr 8;4(4):CD009534. doi: 10.1002/14651858.CD009534.pub2. Epub ahead of print. PMID: 25851268; PMCID: PMC8407041. Accessed October 15, 2021. Cai T, Mazzoli S, Mondaini N, Meacci F, Nesi G, D'Elia C, Malossini G, Boddi V, Bartoletti R. The role of asymptomatic bacteriuria in young women with recurrent urinary tract infections: to treat or not to treat? Clin Infect Dis. 2012 Sep;55(6):771-7. doi: 10.1093/cid/cis534. Epub 2012 Jun 7. PubMed PMID: 22677710. Considering this, the Infectious Diseases Society of America (IDSA) specifically stated that screening for ABU in patient populations that would not benefit from ABU treatment is not indicated. This includes:

1) Elderly people with disabilities (including those staying in chronic care facilities).

2) Patients with diabetes.

3) Transplant recipients (except for the first month after kidney transplant).

4) People with spinal cord injury and urination disorders.

5) People with a bladder catheter.

6) Patients before elective surgical treatment other than urologic surgery (including elective arthroplasty).


ABU requires no treatment, except for:

1) Pregnant patients (see Urinary Tract Infections in Pregnant Women).

2) Patients scheduled for urologic procedures when bleeding is anticipated, including transurethral resection of the prostate. In such individuals start antibacterial prophylaxis on the evening prior to the procedure using an antibiotic selected on the basis of culture results (preferably a fluoroquinolone) and continue only in case of delayed catheter removal.

We would love to hear from you

Comments, mistakes, suggestions?

We use cookies to ensure you get the best browsing experience on our website. Refer to our Cookies Information and Privacy Policy for more details.