What is the first line treatment for uncomplicated urinary tract infections (UTIs)?

First-Line Treatment for Uncomplicated UTI

For uncomplicated urinary tract infections in women, use nitrofurantoin (100 mg twice daily for 5 days), fosfomycin trometamol (3 g single dose), or trimethoprim-sulfamethoxazole (160/800 mg twice daily for 3 days) as first-line therapy, with the choice guided by local antibiogram data. 1, 2

Recommended First-Line Agents

The three first-line antibiotics are equally effective but differ in resistance patterns and administration:

• Nitrofurantoin monohydrate/macrocrystals: 100 mg twice daily for 5 days 1, 2

  • Minimal resistance development (only 2.6% prevalence with initial infection, 5.7% at 9 months) 1
  • Low collateral damage to protective vaginal and periurethral microbiota 2
  • Avoid if early pyelonephritis is suspected 2

• Fosfomycin trometamol: 3 g single dose 1, 2

  • Convenient single-dose regimen with excellent patient compliance 2
  • Slightly lower efficacy than other first-line agents but acceptable for uncomplicated cystitis 1, 2

• Trimethoprim-sulfamethoxazole (TMP-SMX): 160/800 mg twice daily for 3 days 1, 2

  • Use only if local resistance rates are <20% or if the infecting strain is known to be susceptible 2
  • High likelihood of persistent resistance in some regions (78.3% in Irish cohorts) 1

Critical Treatment Principles

Duration of therapy should be as short as reasonable, generally no longer than 7 days, to minimize resistance and preserve protective microbiota. 1

When to Obtain Urine Culture

Urine culture is not routinely needed for typical uncomplicated cystitis but is indicated for: 1, 2

• Suspected acute pyelonephritis 1
• Symptoms that do not resolve or recur within 4 weeks after treatment 1
• Women presenting with atypical symptoms 1
• Pregnant women 1
• Recurrent UTI patients (obtain culture with each symptomatic episode prior to treatment) 1, 2

Agents to Avoid as First-Line

Fluoroquinolones should not be used for uncomplicated UTIs due to FDA advisory warnings about disabling and serious adverse effects resulting in an unfavorable risk-benefit ratio. 1

Beta-lactam antibiotics are not first-line therapy because of collateral damage effects and propensity to promote more rapid UTI recurrence. 1

Alternative for Mild Symptoms

For women with mild to moderate symptoms, symptomatic therapy with ibuprofen may be considered as an alternative to antimicrobial treatment after discussing risks and benefits with the patient. 1, 2

Common Pitfalls

• Do not treat asymptomatic bacteriuria except in pregnant women or before invasive urologic procedures, as treatment increases antimicrobial resistance risk without benefit. 1, 2
• Do not use longer courses or more potent antibiotics for recurrent UTI as this approach increases recurrence rates by disrupting protective microbiota. 1
• Avoid fluoroquinolones and cephalosporins as they cause greater collateral damage, alter fecal microbiota, and increase Clostridium difficile infection risk. 1