What is the first-line treatment for urinary tract infection (UTI) caused by Escherichia coli (E. coli)?

From the Guidelines

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

Treatment Options

• For patients with uncomplicated cystitis, nitrofurantoin is a reasonable drug of choice, based on robust evidence of efficacy and its ability to spare use of more systemically active agents for treating other infections 1.
• Trimethoprim-sulfamethoxazole (TMP/SMX) and fosfomycin are also considered first-line treatments for uncomplicated UTIs, with the choice of antibiotic depending on local resistance rates and patient-specific factors 1.
• For patients with pyelonephritis, TMP/SMX or a first-generation cephalosporin represent reasonable first-line agents, but should be dependent upon local resistance rates 1.

Dosage and Duration

• The recommended dosage and duration of treatment vary depending on the specific antibiotic and patient population, but typical regimens include:
  • Nitrofurantoin: 50-100 mg four times a day for 5 days 1.
  • TMP/SMX: 160/800 mg twice a day for 3 days 1.
  • Fosfomycin: 3 g single dose for uncomplicated cystitis 1.

Considerations

• The choice of antibiotic should be guided by local resistance rates and patient-specific factors, such as allergy history and renal function 1.
• Fluoroquinolones may be considered for patients with complicated UTIs or those who have failed first-line treatment, but their use should be guided by local resistance rates and patient-specific factors due to concerns about resistance and adverse effects 1.

From the Research

First-Line Treatment for Urinary Tract Infection (UTI) Caused by Escherichia coli (E. coli)

The first-line treatment for UTI caused by E. coli depends on the type of UTI and the patient's specific situation.

• For uncomplicated cystitis, the recommended first-line empiric antibiotic therapy is:
  • Nitrofurantoin 2, 3, 4, 5
  • Fosfomycin 2, 3, 4
  • Pivmecillinam 3, 4
• For uncomplicated pyelonephritis, fluoroquinolones are still recommended in sufficiently high dosage due to the resistance rates of E. coli still being below 10% and the superior effectivity compared to other antibiotics 3
• Trimethoprim-sulfamethoxazole is no longer regarded as the first-line agent in the empiric treatment of uncomplicated cystitis, unless the regional resistance rate is below 20% 3, 6
• Amoxicillin-clavulanic acid is recommended as first-line therapy for pyelonephritis or complicated UTI 2

Considerations for Antibiotic Resistance

• Increasing resistance rates of E. coli to trimethoprim-sulfamethoxazole and fluoroquinolones have led to a reassessment of the most appropriate empiric therapy for UTIs 2, 3, 6, 4, 5
• The choice of antibiotic should be based on individual patient risk, bacterial spectrum, antibiotic susceptibility, effectivity of the antimicrobial substance, epidemiological effects, and adverse effects 3
• Local resistance rates and patient-specific factors, such as recent antibiotic use or genitourinary abnormalities, should be considered when selecting an antibiotic 6