From the Guidelines
Asymptomatic bacteriuria can be protective against urinary tract infections (UTIs) through bacterial interference, and treating it is generally not recommended except in specific cases, as stated in the 2024 European Association of Urology guidelines 1. When non-pathogenic bacteria colonize the urinary tract without causing symptoms, they can prevent more virulent bacteria from establishing infection. These commensal bacteria compete for nutrients and attachment sites on the bladder epithelium, making it difficult for pathogenic bacteria to gain a foothold. They may also produce bacteriocins, which are antimicrobial substances that inhibit the growth of other bacterial species. Some key points to consider include:
- Asymptomatic bacteriuria is common and corresponds to commensal colonization 1.
- The spectrum of bacteria in asymptomatic bacteriuria is similar to species found in uncomplicated or complicated UTIs, depending on the presence of risk factors 1.
- Clinical studies have shown that asymptomatic bacteriuria may protect against superinfecting symptomatic UTI, and thus it 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 strain 1.
- A recent systematic review of antimicrobial treatment of asymptomatic bacteriuria in noncatheterized adults concluded that antimicrobial treatment of asymptomatic bacteriuria may improve short-term microbiologic outcomes, but the microbiologic resolution is not sustained and there is no measurable improvement in morbidity or mortality 1.
- There is some evidence suggesting that persistent asymptomatic bacteriuria may protect from symptomatic UTI, as an early randomized trial of therapy for women with asymptomatic bacteriuria reported that most symptomatic reinfections occurred in the antimicrobial treatment group 1. In summary, the current evidence suggests that asymptomatic bacteriuria can be protective against UTIs, and treatment should be reserved for specific cases, such as pregnant women, to avoid disrupting this natural protection and potentially increasing the risk of symptomatic UTIs 1.
From the Research
Asymptomatic Bacteruria and UTI Protection
- Asymptomatic bacteruria (ABU) can be protective against urinary tract infections (UTIs) in certain individuals, as suggested by research 2, 3.
- A study found that treating ABU in young women with recurrent UTIs may not be beneficial and could even increase the risk of recurrence 3.
- The presence of ABU may play a protective role in preventing symptomatic recurrence of UTIs in some cases 3.
- However, treatment of ABU is recommended in specific situations, such as in pregnant women and before certain urological surgeries 4, 5.
Benefits and Harms of Treating Asymptomatic Bacteruria
- Treating ABU can be harmful and may lead to adverse effects, such as antimicrobial resistance and increased healthcare costs 4, 5.
- The Infectious Disease Society of America (IDSA) guidelines recommend treating ABU in pregnant women and individuals undergoing endoscopic urologic procedures, but not in other cases unless there is evidence of potential benefit 5.
- Antibiotic stewardship programs aim to reduce unnecessary treatment of ABU and promote appropriate screening and treatment only when beneficial 5.
Specific Patient Groups and Asymptomatic Bacteruria
- Pregnant women with ABU should be treated to reduce the risk of symptomatic UTIs, low birthweight, and preterm delivery 4, 5.
- Individuals undergoing transurethral resection surgery should be treated for ABU to reduce the risk of postoperative UTIs 4.
- However, treatment of ABU is not recommended for patients with diabetes, neutropenia, spinal cord injuries, or indwelling urinary catheters, as it has not been shown to improve clinical outcomes 5.