From the Guidelines
Asymptomatic bacteriuria (ASB) is generally a benign condition that does not require treatment in most cases, as it may even protect against superinfecting symptomatic UTI 1.
Key Points
- ASB is defined as a mid-stream sample of urine showing bacterial growth >10^5 cfu/ml in two consecutive samples in women and in a single sample in men 1.
- The spectrum of bacteria in ASB is similar to species found in uncomplicated or complicated UTIs, depending on the presence of risk factors 1.
- Clinical studies have shown that ASB may protect against superinfecting symptomatic UTI, and thus ASB should only be treated in cases of proven benefit for the patient to avoid the risk of selecting antimicrobial resistance and eradicating a potentially protective ASB strain 1.
- Treatment of ASB is only recommended in certain cases, such as in pregnant women, where it can reduce the incidence of symptomatic maternal urinary tract infections and low birthweight 1.
- In men and nonpregnant women, screening for ASB is not recommended, as it is ineffective in improving clinical outcomes and may lead to unnecessary antibiotic use and resistance 1.
Special Considerations
- Pregnant women should be screened for ASB at 12-16 weeks' gestation or at the first prenatal visit, if later, and receive antibiotic therapy directed at the cultured organism and follow-up monitoring if the results are positive 1.
- Screening for ASB is also recommended before certain urologic procedures, such as transurethral resection of the prostate, to prevent post-procedure infections 1.
- In cases where ASB is detected, it is essential to consider the potential benefits and harms of treatment and to individualize care based on the patient's specific circumstances and risk factors 1.
From the Research
Definition and Prevalence of Asymptomatic Bacteriuria (ASB)
- ASB is a common clinical finding characterized by the presence of bacteria in the urine of an individual without signs or symptoms suggestive of urinary tract infection 2.
- The prevalence of ASB varies widely in different patient populations, including healthy adults, institutionalized elderly, pregnant women, and immune-compromised patients 3.
- ASB is more common in women than men, and the incidence increases with age, with older women having a higher incidence of ASB 4.
Significance of ASB
- ASB is often managed inappropriately, with unnecessary antibiotic treatment that can lead to unwanted consequences such as increased antimicrobial resistance, Clostridioides difficile infection, and increased healthcare cost 2, 4.
- Treatment of ASB with antimicrobial therapy may improve short-term microbiologic outcomes, but the clinical significance is diminished because the effect is not sustained, and there is no measurable improvement in morbidity or mortality 2.
- ASB does not typically lead to urinary tract infections, and antibiotic treatment has not been shown to improve patient outcomes in most scenarios 4.
Management and Treatment of ASB
- The Infectious Diseases Society of America (IDSA) has updated its guidelines for the management of ASB, emphasizing the risks and benefits of treating the condition 4.
- Screening and treatment of ASB are recommended for pregnant women and individuals undergoing endoscopic urologic procedures, but not for individuals with diabetes, neutropenia, spinal cord injuries, or indwelling urinary catheters 4.
- Antibiotic stewardship programs have been implemented to reduce unnecessary treatment of ASB and promote appropriate use of antimicrobial agents 4.