Can a Silent Kidney Infection or Genetic Predisposition Underlie Recurrent UTIs?

, University of Calgary and Alberta Children's Hospital


Medscape General Medicine. 1996;1(1) 

In This Article


Table I - Risk Factors for Uncomplicated UTIs in Women

  • Short urethra

  • Sexual intercourse

  • Delayed postcoital urination

  • Use of a diaphragm and spermicide for birth control

  • Increased uroepithelial receptor density that creates genetic predisposition

From Stamm and Hooton.[8]

Table II - Major Causes of the Acute Urethral Syndrome in Women

Condition Pathogen(s) Pyuria Main symptoms
Cystitis Escherichia coli Usually Dysuria, frequency, Staphylococcus urgency, suprapubic saprophyticus pain/tenderness Other gram-negative organisms Urethritis Chlamydia trachomatis Usually Dysuria, mild frequency, Neisseria gonorrhoeae vaginal discharge or Mycoplasma hominis/ bleeding (due to Ureaplasma urealyticum concomitant cervicitis), Herpes simplex virus urethral bleeding when swabs collected genital ulcers Vaginitis Candida sp Rarely Vaginal discharge or Trichomonas vaginalis odor, vulvo-vaginal pruritus, external dysuria, dyspareunia, no frequency, vaginitis on exam From Stamm and Hooton[8]; and Stamm et al.[22]


Table III - Interpretation of Urine Microscopy

  • Pyuria (WBC in the urine)

    • Unspun urine: 5-10 WBC/hpf

    • Spun urine: 50-100 WBC/hpf

  • Significant bacteriuria (>108 bacteria or CFU/L)

    • Unspun urine: 1 bacteria/hpf

    • Spun urine: 10 bacteria/hpf

hpf = high-power field.

Table IV - Short-Course Antibiotic Therapy: Cystitis

Effective 3-day Regimens
Trimethoprim/sulfamethoxazole (TMP/SMX) 160mg/800mg bid Amoxicillin 500mg PO tid Cephalexin 250-500mg PO qid Ciprofloxacin 250-500mg PO bid Nitrofurantoin 100mg PO qid Norfloxacin 400mg PO bid Trimethoprim 100mg PO bid From Stamm and Hooton.[8]

Table V - Continuous Low-Dose Antibacterial Prophylaxis: Single Daily Dose

Ciprofloxacin 250mg PO Nitrofurantoin 200mg PO Norfloxacin 800mg PO Trimethoprim 400mg PO Trimethoprim/sulfamethoxazole (TMP/SMX) 320mg/1600mg PO From Stamm and Hooton,[8] Stamm WE et al,[22] Stamm WE et al,[24] Johnson and Stamm.[26]