- Colonizing organisms (Escherichia coli · Enterococcus species · Klebsiella species · other commensal uropathogens)
- Clinical context (Bladder colonization without urinary symptoms · often without pyuria · microbiology may differ from symptomatic UTI strains)
First-line therapy
No antibiotic therapy • —
Duration: Not indicated · Otherwise healthy children — observe; treat only if symptomatic UTI develops (IDSA, ESPU/EAU, AAP, CPS, NICE)
Exceptions — culture-directed therapy only • per susceptibility
Duration: Per exception · No empiric regimens — obtain culture and tailor to antibiogram and local protocol
- • Invasive endourologic procedures with anticipated mucosal trauma (e.g. resection, incision): screen for ASB and treat with targeted antimicrobial therapy before procedure — initiate 30–60 min preprocedure; short course (1–2 doses) preferred over prolonged therapy (IDSA 2019, EAU/ESPU).
- • Procedures without mucosal breach (e.g. uncomplicated diagnostic cystoscopy, routine catheter exchange): routine antimicrobial treatment of ASB generally not recommended (IDSA).
- • Pending MCUG/VCUG when imaging is indicated: short-term antibiotic prophylaxis until examination may be started per ESPU/EAU — distinct from routine eradication of ASB.
- • Renal transplant recipients: IDSA recommends against screening for or treating ASB >1 month post-transplant; no recommendation for the first month — manage per transplant nephrology/infectious diseases team.
- • Neurogenic bladder / clean intermittent catheterization: bacteriuria alone without urinary symptoms or systemic illness may not require treatment — evaluate for true UTI when pyuria and compatible symptoms are present.
Clinical notes
- • Definition: significant growth of a single uropathogen in appropriately collected urine without urinary tract symptoms and without pyuria — colonization, not UTI (ESPU/EAU, IDSA, AAP).
- • Diagnostic criteria: culture thresholds depend on collection — typically ≥10^5 CFU/mL (≥10^8 CFU/L) without catheter; catheter ≥50,000 CFU/mL or SPA ≥1,000 CFU/mL must be interpreted with absence of pyuria and symptoms; true UTI requires pyuria plus compatible clinical findings (AAP, IDSA).
- • Repeat urine culture: when diagnosis uncertain (intermediate counts); before invasive urologic procedures with mucosal trauma; if symptoms develop; to confirm bag-screen positives by catheter or SPA — not for routine surveillance of ASB.
- • Treatment NOT indicated: do not screen for or treat ASB in otherwise healthy infants and children (strong recommendation, IDSA); no benefit for preventing symptomatic UTI or renal scarring; increases resistance, adverse effects, and inappropriate antimicrobial use (CPS, NICE, ESPU/EAU).
- • Referral: urology or nephrology for recurrent symptomatic UTI, abnormal renal/bladder ultrasound, complex CAKUT, neurogenic bladder, renal transplant, or planned invasive urologic procedures requiring perioperative culture-directed management.
- • IDSA — Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria (2019)
- • AAP — Urinary Tract Infection Clinical Practice Guideline (2011)
- • AAP Red Book — Urinary Tract Infections (2024)
+ 4 more
- • Canadian Paediatric Society — Urinary tract infections in children (2024)
- • ESPU / EAU Guidelines on Paediatric Urology (UTI sections) (2024)
- • NICE NG111 — Urinary tract infection (principles applicable) (2018)
- • WHO Pocket Book of Hospital Care for Children (2022)