What is the first-line treatment for uncomplicated urinary tract infections (UTIs) caused by Escherichia coli (E. coli)?

First-Line Treatment for UTI Caused by E. coli

For uncomplicated urinary tract infections caused by E. coli, the first-line treatments are fosfomycin trometamol (3g single dose), nitrofurantoin (100mg twice daily for 5 days), or pivmecillinam (400mg three times daily for 3-5 days). 1, 2

Recommended First-Line Options

Fosfomycin Trometamol

• Single 3g dose, making it highly convenient for patient adherence 3, 1
• FDA-approved specifically for uncomplicated UTIs due to E. coli 3
• Low resistance rates (<6%) compared to other antimicrobials 4

Nitrofurantoin

• 100mg twice daily for 5 days (macrocrystal/monohydrate formulation) 1
• Excellent activity against E. coli with persistently low resistance rates 1, 2
• Resistance rates decrease significantly over time (20.2% at 3 months to 5.7% at 9 months) 1

Pivmecillinam

• 400mg three times daily for 3-5 days 1
• Particularly effective against E. coli with low resistance rates 1, 2

Second-Line Options

• Trimethoprim-sulfamethoxazole (160/800mg twice daily for 3 days) - only if local E. coli resistance is <20% 1, 5
• Cephalosporins (e.g., cefadroxil 500mg twice daily for 3 days) - if local E. coli resistance is <20% 1
• Beta-lactams (e.g., amoxicillin-clavulanate) - less preferred due to higher recurrence rates 1, 2

Antibiotics to Avoid as First-Line

• Fluoroquinolones (e.g., ciprofloxacin, levofloxacin) should not be used as first-line therapy for uncomplicated UTIs 1, 6, 7
  • FDA issued an advisory warning against fluoroquinolones for uncomplicated UTIs due to unfavorable risk-benefit ratio 1
  • Associated with more severe adverse effects and collateral damage to gut microbiota 1
  • Should be reserved for complicated UTIs or when other options cannot be used 6

Treatment Considerations

• Local antimicrobial resistance patterns should guide empiric therapy selection 2, 7
• Short-course therapy is preferred to minimize risk of resistance development 8
• Urine culture is not necessary for uncomplicated cases with typical symptoms 1
• Culture should be obtained if symptoms persist or recur within 4 weeks of treatment 1

Special Populations

• For men with UTI, longer treatment duration (7 days) with trimethoprim-sulfamethoxazole is recommended 1
• For pregnant women, nitrofurantoin is preferred (except in first trimester), while trimethoprim should be avoided in first trimester and trimethoprim-sulfamethoxazole avoided in last trimester 1

Antibiotic Stewardship Principles

• Use narrow-spectrum antibiotics when possible 1
• Avoid fluoroquinolones and cephalosporins as first-line due to their propensity to alter fecal microbiota and promote resistance 1
• Treat according to clinical practice guidelines using short-duration therapy 1
• Consider local resistance patterns when selecting empiric therapy 2, 7