asymptomatic bacteriuria

• related: ID

Asymptomatic bacteriuria:

• definition: presence of at least 10^5 CFU/mL of a uropathogen from 2 consecutive voided urine specimens in women or one specimen in men, or more than 10^2 CFU/mL of one bacterial species from a catheterized urine specimen in women or men, in all cases without local or systemic signs or symptoms of active infection.
• The prevalence of asymptomatic bacteriuria is as low as 1% to 5% in healthy premenopausal women (2%-10% in pregnant women) and nearly 100% in patients with long-term indwelling urinary catheters.

Treatment:

• The presence of pyuria accompanying asymptomatic bacteriuria is not an indication for antimicrobial treatment. Although bacteriuria increases the risk of symptomatic UTI, treatment of asymptomatic bacteriuria neither decreases the frequency of symptomatic infections nor improves other outcomes. Inappropriate treatment of asymptomatic bacteriuria is a major driver of antimicrobial resistance, particularly in health care facilities.
• Treatment of asymptomatic bacteriuria is, however, indicated in pregnant women and in patients scheduled to undergo an invasive procedure involving the urinary tract.

The indication for antimicrobial therapy in this patient is an invasive urologic procedure. Because urine is a sterile body fluid, the presence of significant bacteriuria is considered to be an infection. In men, either 10^5 cfu/mL of bacteria from voided urine or at least 10^2 cfu/mL of a single bacterial species from a clean intermittent catheterized sample is required to distinguish true bacteriuria from contamination. Asymptomatic bacteriuria (ASB) is diagnosed when no signs or symptoms of active infection referable to the urinary tract are present. Depending on variables such as age and genitourinary abnormalities, older adult men have an ASB prevalence of approximately 5% to 20% in the community, rising to 15% to 40% in long-term care facilities. It is important to recognize that screening for and possibly treating asymptomatic bacteriuria is supported by only two indications: pregnancy and risk mitigation before an invasive urologic procedure. The use of prophylactic antibiotics before minor noninvasive urologic interventions without mucosal bleeding does not provide any benefit and is not recommended.

Likewise, screening for and treating ASB in patients about to undergo orthopedic surgery, including total joint arthroplasty, is without proven merit because it is not a cause of postoperative surgical site infection.

Data are insufficient to advocate the routine treatment of ASB in kidney transplant recipients or patients with diabetes.