Positive urine culture without symptoms (asymptomatic bacteriuria, urinary colonisation)
BioMG follows French guidelines. Adapt it to the guidelines and the tests available where you practise.
Positive urine culture without urinary symptoms (outside pregnancy): do not treat
- No tests: no antibiotic, no repeat urine microscopy and culture.
- Check that there are no urinary signs or fever; in an elderly patient who is confused or has fallen without urinary signs or fever, look for another cause.
Do not order
- “Screening” urine microscopy and culture in a non-pregnant woman, a dependent older person (at home or in an institution), a person with diabetes, a person with spinal cord injury or a catheter carrier, without symptoms: strong recommendation against [2].
- Urine microscopy and culture before non-urological surgery, notably before elective hip or knee arthroplasty or cardiovascular surgery: do not screen or treat [2,3].
- Follow-up urine microscopy and culture after treatment of a urinary tract infection that has resolved well: unnecessary, since persistent colonisation would not be treated (SPILF reasoning for urinary tract infection in men) [4].
- Treatment of asymptomatic candiduria (outside the preoperative period of urological surgery): not recommended [3].
The two situations where you screen and treat: pregnancy, urological procedure
Before a urological procedure involving contact with urine
- Urine microscopy and culture with susceptibility testing (preoperative screening)if neededElective procedure in contact with urine (urological endoscopy with mucosal trauma, transurethral resection of the prostate or bladder), or change of ureteral stent (double J) [2,3]. The 2026 AFU/SPILF good practice recommendation (RBP) recommends it before transurethral resection of the prostate or bladder, endoscopic prostate enucleation or vaporisation, ureteroscopy, percutaneous nephrolithotomy, urethroplasty, urethrotomy, ureteroplasty, insertion or change of a JJ stent or nephrostomy, and urodynamic assessment, within the 10 days before the procedure [9].
- Pregnancy: see the page Urinary tract infection and pregnancy (monthly dipstick from the 4th month, urine microscopy and culture if positive; urine microscopy and culture straight away, at the start of pregnancy then every month from the 4th month, if history of urinary tract infection, diabetes or uropathy).
Do not order
- Urine microscopy and culture before a cystoscopy, whatever the indication: strongly discouraged (grade B) [9]; the 2015 SPILF/AFU said it was optional [3].
- Urine microscopy and culture before a BCG instillation: not justified, BCG eradicates bacteriuria [3,9].
- Screening before insertion of an artificial urinary sphincter or a penile prosthesis: the IDSA suggests not doing it (standard antibiotic prophylaxis) [2]; the 2026 AFU/SPILF RBP also recommends not screening before an artificial sphincter, penile implant or testicular prosthesis [9].
- Urine dipstick to screen for colonisation before a urological procedure: strongly discouraged, urine microscopy and culture is the reference method [9].
- Urine microscopy and culture before total prostatectomy, cystectomy, nephrectomy, prostate biopsy, intradetrusor botulinum toxin injection, prostate embolisation or change of urinary catheter or suprapubic catheter: screening not recommended [9].
Patient with an indwelling catheter or intermittent catheterisation: when to send a urine culture
Only if signs of infection
- Urine microscopy and culture taken by puncture of the catheter sampling port, after disinfectionif neededFever, hypothermia (< 36 °C), hypotension, altered mental state, general malaise or lethargy without other cause, or urinary signs persisting after catheter removal [3].
Do not order
- Urine dipstick in a catheter carrier: not recommended for diagnosis [3].
- Surveillance urine microscopy and culture or routine urine microscopy and culture in a catheter carrier without symptoms: do not screen [2,3].
- Changing the catheter in order to obtain the urine culture: not recommended [3].
- Follow-up urine microscopy and culture 48 to 72 hours after the start of treatment, unless there is no clinical response: not recommended [3].
Sources (11)
- US Preventive Services Task Force ; Owens DK, Davidson KW, Krist AH, et al. Screening for asymptomatic bacteriuria in adults: US Preventive Services Task Force recommendation statement. JAMA. 2019;322(12):1188-1194.
- Nicolle LE, Gupta K, Bradley SF, et al. Clinical Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2019;68(10):e83-e110.
- SPILF, Association française d'urologie (AFU), Société française d'hygiène hospitalière (SF2H). Révision des recommandations de bonne pratique pour la prise en charge et la prévention des infections urinaires associées aux soins (IUAS) de l'adulte. Version finale du 7 mai 2015.
- Société de pathologie infectieuse de langue française (SPILF). Diagnostic et antibiothérapie des infections urinaires bactériennes communautaires de l'adulte. Mise au point, texte court, actualisation au 11 décembre 2015.
- Haute Autorité de santé, SPILF. Choix et durées d'antibiothérapies : cystite aiguë simple, à risque de complication ou récidivante, de la femme. Fiche mémo, validée le 15 juillet 2021, mise à jour le 13 mai 2025.
- Bonkat G, Kranz J, Cai T, et al. EAU Guidelines on Urological Infections. Association européenne d'urologie (EAU), édition 2026 (mise à jour partielle de mars 2026).
- National Institute for Health and Care Excellence (NICE). Urinary tract infection (lower): antimicrobial prescribing. NICE guideline NG109, 31 octobre 2018.
- UK Health Security Agency (UKHSA). Diagnosis of urinary tract infections: quick reference tools for primary care. Outils « Diagnostic decision tool for suspected UTI in adults over 65 years » et « … adults with a urinary catheter » (CAUTI), version 4.0, mai 2025.
- Association française d'urologie (comités des pratiques professionnelles et d'infectiologie), avec la SPILF. Place de l'ECBU avant une prise en charge urologique chirurgicale ou interventionnelle chez l'adulte et modalités de traitement en cas de colonisation. Recommandation de bonne pratique, synthèse, janvier 2026 (mise en ligne le 4 mars 2026), et tableau de synthèse « indications de l'ECBU ».
- UK National Screening Committee (UK NSC). Asymptomatic bacteriuria (programme de dépistage prénatal) : recommandation fondée sur la revue de novembre 2020. Page consultée le 29 octobre 2026.
- National Institute for Health and Care Excellence (NICE). Urinary tract infection (catheter-associated): antimicrobial prescribing. NICE guideline NG113, 23 novembre 2018.