What is the appropriate treatment for a patient with a urinary tract infection (UTI)?

Treatment of Urinary Tract Infections (UTIs)

The appropriate treatment for urinary tract infections should be based on whether the infection is uncomplicated or complicated, with first-line therapy for uncomplicated UTIs including nitrofurantoin for 5 days, trimethoprim-sulfamethoxazole (TMP-SMX) for 3 days (if local resistance rates are <20%), or fosfomycin as a single dose. 1, 2, 3

Classification of UTIs

• UTIs are classified as uncomplicated (occurring in patients without structural or functional abnormalities of the urinary tract and without relevant comorbidities) or complicated (occurring in patients with underlying structural or medical problems) 1
• Uncomplicated UTIs include both lower tract infection (cystitis) and upper tract infection (pyelonephritis), though repeated pyelonephritis should prompt consideration of a complicated etiology 1
• Complicated UTIs are associated with factors such as urinary obstruction, foreign bodies, incomplete voiding, vesicoureteral reflux, pregnancy, diabetes, immunosuppression, and recent instrumentation 1

Diagnosis

• Symptoms of UTI typically include dysuria, frequency, urgency, hematuria, and suprapubic pain 2
• In women with typical symptoms and no vaginal discharge, clinical diagnosis is often sufficient for uncomplicated UTIs 3
• A urine culture should be obtained in the following situations:
  • Suspected pyelonephritis
  • Symptoms that don't resolve or recur within 4 weeks after treatment
  • Atypical symptoms
  • Pregnant women
  • Recurrent UTIs
  • Men with UTI symptoms 1

Treatment Algorithm for UTIs

Uncomplicated UTIs in Women

1. First-line treatment options:

   • Nitrofurantoin 100 mg twice daily for 5 days 1, 3
   • Fosfomycin trometamol 3 g single dose 1
   • TMP-SMX 160/800 mg twice daily for 3 days (if local resistance <20%) 1, 4
   • Pivmecillinam 400 mg three times daily for 3-5 days 1

2. Alternative options (when first-line agents cannot be used):

   • Cephalosporins (e.g., cefadroxil 500 mg twice daily for 3 days) 1
   • Trimethoprim 200 mg twice daily for 5 days (avoid in first trimester of pregnancy) 1

Complicated UTIs

1. Empiric treatment options:

   • Amoxicillin plus an aminoglycoside
   • A second-generation cephalosporin plus an aminoglycoside
   • An intravenous third-generation cephalosporin 1

2. Treatment duration:

   • Generally 7-14 days (14 days for men when prostatitis cannot be excluded)
   • When the patient is hemodynamically stable and has been afebrile for at least 48 hours, a shorter treatment duration (7 days) may be considered 1

UTIs in Men

• TMP-SMX 160/800 mg twice daily for 7 days
• Fluoroquinolones can also be prescribed in accordance with local susceptibility testing 1
• Longer treatment duration (7 days) is typically required 3

Pyelonephritis

• Third-generation cephalosporins are preferred for management 2
• If fluoroquinolones are used (when resistance is <10%), an initial intravenous dose of a long-acting parenteral antimicrobial (e.g., ceftriaxone) should be administered 1
• Treatment duration is typically 7-14 days 1

Special Considerations

Recurrent UTIs

• Defined as at least three episodes of infection within the preceding 12 months or two UTIs in the last 6 months 1
• Non-antimicrobial preventive measures should be attempted first:
  • Increased fluid intake for premenopausal women 1
  • Vaginal estrogen replacement in postmenopausal women 1
  • Immunoactive prophylaxis 1
  • Methenamine hippurate for women without urinary tract abnormalities 1
• Continuous or postcoital antimicrobial prophylaxis when non-antimicrobial interventions have failed 1
• Self-administered short-term antimicrobial therapy for patients with good compliance 1

Asymptomatic Bacteriuria

• Should not be treated in most populations 1
• Exceptions include pregnant women and patients scheduled to undergo invasive urinary tract procedures 1

Catheter-Associated UTIs

• Signs include new onset or worsening of fever, altered mental status, flank pain, and pelvic discomfort 1
• Catheterization duration is the most important risk factor 1
• Treatment should follow guidelines for complicated UTIs 1

Common Pitfalls and Caveats

• Avoid fluoroquinolones for empiric treatment due to increased rates of resistance, especially if the patient has used fluoroquinolones in the last 6 months 1, 5
• Do not treat asymptomatic bacteriuria except in pregnant women and before urologic procedures 1
• Avoid unnecessary urine cultures in uncomplicated UTIs that respond to therapy, as they add substantially to the cost without clinical benefit 6
• Ensure appropriate management of any underlying urological abnormality or complicating factor in complicated UTIs 1
• Consider alternative diagnoses such as vaginitis, vulvar lesions, or sexually transmitted diseases in patients with dysuria but negative urine cultures 6

By following these evidence-based guidelines, clinicians can effectively treat UTIs while practicing antimicrobial stewardship to minimize resistance development.