Asymptomatic bacteriuria (ASB) is specific bacterial growth ≥105 CFU/mL in one and two consecutive midstream urine samples for men and women, respectively >18 years. This definition applies to individuals with no clinical symptoms (1).
- Premenopausal females: 1–5%
- Pregnancy: 2–10%
- Older females and males: 4–19%
- Institutionalized older population: 15–50%
- Variable, increased with age, female gender, sexual activity, and presence of genitourinary (GU) abnormalities
- Pregnancy: 2–10%
- Short- and long-term indwelling catheter 9–23% and 100%, respectively
- Long-term care residents in women 25–50% and men 15–40%
Etiology and Pathophysiology
- Microbiology is similar to that of other UTI, with bacteria originating from periurethral area, vagina, or gut.
- Organisms are less virulent in ASB than those causing UTI.
- The most common organism is Escherichia coli. Other common organisms are Klebsiella pneumoniae, Enterobacter, Proteus mirabilis, Staphylococcus aureus, group B Streptococcus (GBS), and Enterococcus.
Genetic variations that reduce toll-like receptor 4 (TLR4) function have been associated with ASB by lowering innate immune response and delaying bacterial clearance.
- Older age
- Female gender
- Sexual activity, use of diaphragm with spermicide
- GU abnormalities: neurogenic bladder, urinary retention, urinary catheter use (indwelling, intermittent, or condom catheter)
- Institutionalized elderly population
- Diabetes mellitus
- Immunocompromised status
- Spinal cord injuries or functional impairment
Commonly Associated Conditions
Depends on the risk factors
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Domino, Frank J., et al., editors. "Bacteriuria, Asymptomatic." 5-Minute Clinical Consult, 27th ed., Wolters Kluwer, 2020. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688607/all/Bacteriuria__Asymptomatic.
Bacteriuria, Asymptomatic. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2020. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688607/all/Bacteriuria__Asymptomatic. Accessed May 29, 2023.
Bacteriuria, Asymptomatic. (2020). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (27th ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688607/all/Bacteriuria__Asymptomatic
Bacteriuria, Asymptomatic [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2020. [cited 2023 May 29]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688607/all/Bacteriuria__Asymptomatic.
* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Bacteriuria, Asymptomatic ID - 1688607 ED - Domino,Frank J, ED - Baldor,Robert A, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688607/all/Bacteriuria__Asymptomatic PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -