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

Treatment of Urinary Tract Infection (UTI)

For uncomplicated UTI in women, use first-line antibiotics: nitrofurantoin 100 mg twice daily for 5 days, fosfomycin 3g single dose, or trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (only if local resistance is <20%). 1

Uncomplicated Cystitis in Women

First-Line Treatment Options

• Nitrofurantoin: 100 mg twice daily for 5 days 1, 2
• Fosfomycin trometamol: 3g single dose 1, 2
• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 3 days (avoid if local E. coli resistance >20%) 1, 3
• Trimethoprim: 200 mg twice daily for 5 days 1

These agents are preferred because they effectively treat UTI while minimizing collateral damage to normal flora and reducing antimicrobial resistance compared to fluoroquinolones 1.

Second-Line Alternatives

• Cephalosporins (e.g., cefadroxil 500 mg twice daily for 3 days) if local E. coli resistance is <20% 1
• Fluoroquinolones should be avoided for empiric treatment due to increasing resistance rates and should only be used when local resistance is <10%, the patient has β-lactam anaphylaxis, or culture results dictate their use 1

Diagnostic Approach

• Symptomatic women with dysuria plus urgency/frequency can be treated empirically without urinalysis or culture 2
• Obtain urine culture before treatment in cases of: recurrent UTI, treatment failure, atypical symptoms, pregnancy, or history of resistant organisms 1
• Do not treat asymptomatic bacteriuria except in pregnancy or before urologic procedures 1

Uncomplicated Cystitis in Men

Men require 7 days of treatment (longer than women due to potential prostatic involvement) 1:

• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 7 days 1, 3
• Trimethoprim: 200 mg twice daily for 7 days 1
• Nitrofurantoin: 100 mg twice daily for 7 days 2

Always obtain urine culture in men before initiating treatment, and consider urethritis or prostatitis as alternative diagnoses 2.

Uncomplicated Pyelonephritis

For upper tract infection with fever, flank pain, and systemic symptoms 1:

Oral Outpatient Treatment (mild-moderate cases)

• Ciprofloxacin: 500-750 mg twice daily for 7 days (if fluoroquinolone resistance <10%) 1
• Levofloxacin: 750 mg once daily for 5 days 1
• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 14 days 1
• Cefpodoxime: 200 mg twice daily for 10 days 1

Intravenous Treatment (severe cases)

• Third-generation cephalosporin (e.g., ceftriaxone) plus aminoglycoside 1, 4
• Amoxicillin plus aminoglycoside 1
• Switch to oral therapy after 48 hours afebrile and hemodynamically stable 1

Complicated UTI

Complicated UTI occurs with structural/functional urinary tract abnormalities, immunosuppression, pregnancy, diabetes, catheterization, or male sex 1.

Empiric Treatment for Systemic Symptoms

• Combination therapy: Third-generation cephalosporin (IV) plus aminoglycoside 1
• Alternative: Amoxicillin plus aminoglycoside 1
• Duration: 7-14 days (14 days for men when prostatitis cannot be excluded) 1

Always obtain urine culture and tailor therapy based on susceptibility results 1. The microbial spectrum is broader than uncomplicated UTI, including E. coli, Proteus, Klebsiella, Pseudomonas, Serratia, and Enterococcus 1.

Address the underlying urological abnormality—antimicrobial therapy alone is insufficient 1.

Recurrent UTI (≥3 episodes/year or 2 episodes/6 months)

Non-Antimicrobial Prevention (try first)

• Vaginal estrogen in postmenopausal women (strong recommendation) 1
• Increased fluid intake 1
• Post-coital voiding 1
• Avoid spermicide-containing contraceptives 1
• Immunoactive prophylaxis 1
• Methenamine hippurate for women without urinary tract abnormalities 1, 2

Antimicrobial Prophylaxis (when non-antimicrobial measures fail)

Use continuous or post-coital prophylaxis 1:

• Low-dose nitrofurantoin, trimethoprim-sulfamethoxazole, or trimethoprim
• Patient-initiated self-start treatment is appropriate for select patients with good compliance 1

Diagnostic Workup

• Do not routinely perform cystoscopy or imaging in women <40 years without risk factors 1
• Obtain urine culture with each symptomatic episode to document recurrence and guide therapy 1

Key Pitfalls to Avoid

• Do not use fluoroquinolones empirically due to rising resistance and adverse effects; reserve for culture-directed therapy 1
• Do not obtain post-treatment cultures in asymptomatic patients—symptom resolution is sufficient 1
• Do not treat asymptomatic bacteriuria except in pregnancy or before urologic procedures 1
• Avoid prolonged antibiotic courses—treat for the shortest effective duration (generally ≤7 days for uncomplicated UTI) 1
• Consider alternative diagnoses (vaginitis, urethritis, interstitial cystitis) when symptoms persist despite negative cultures 1