[Clin Infect Dis 2005; 40:643-54]
- Asymptomatic bacteriuria (ASB) is a colonization state and does NOT indicate an infection that requires treatment. Pyuria is very common in patients with asymptomatic bacteriuria and is also NOT an indication for antibiotic treatment.
asymptomatic females - two consecutive voided urine cultures with ≥ 108 cfu/L of same organism +/- pyuria.
asymptomatic males - one voided urine culture with ≥ 108 cfu/L of ≥ 1 organism +/- pyuria.
catheterized patients - catheter urine culture with ≥105 cfu/L of ≥ 1 organism +/- pyuria and no symptoms of UTI.
Incidence of asymptomatic bacteriuria:
young adults: 1-3%
>65 years old: 20% females, 10% males
>80 years old: 50% females, 30% males
short-term (< 30 days) indwelling: 9-23%
long-term (≥ 30 days) indwelling: 100%
- Hospital > nursing home > community
Associated laboratory findings:
- Routine screening cultures not recommended, unless prior to GU surgery or pregnant. NB: cloudy/foul smelling urine alone is not an indication for urine culture.
- Up to 90% of elderly patients with asymptomatic bacteriuria have pyuria, hence pyuria is not a valid diagnostic criterion for UTI in this patient population; clinical correlation required.
- NO evidence that antibiotic therapy of asymptomatic bacteriuria decreases symptomatic UTI.
- NO evidence that antibiotic therapy of asymptomatic bacteriuria is of any benefit EXCEPT:
prior to genitourinary (GU) procedures in which mucosal bleeding/ trauma is expected, or
- Inappropriate treatment of ASB is a significant contributor to antimicrobial overuse, antimicrobial resistance, and adverse drug effects including Clostridioides (Clostridium) difficile infection.
- Antibiotic therapy of asymptomatic bacteriuria is specifically NOT recommended:
young women with recurrent UTI as it:
increases risk of recurrent UTI
increases risk of multi-drug resistant E. coli [Clin Infect Dis 2012;55:771-7]
renal transplant patients
prior to minor urologic procedures (no mucosal bleeding)
prior to orthopedic surgery
prior to catheter removal
patients with long term catheterization
patients with spinal cord injury.
- Asymptomatic bacteriuria is NOT associated with incontinence, hypertension, or decreased renal function in the elderly.