What is the recommended treatment for a simple urinary tract infection (UTI) in an otherwise healthy adult?

Treatment of Simple (Uncomplicated) Urinary Tract Infection

For otherwise healthy adult women with uncomplicated cystitis, nitrofurantoin 100 mg twice daily for 5 days is the recommended first-line treatment, with fosfomycin 3g single dose and trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days as equally appropriate alternatives. 1, 2

First-Line Treatment Options for Women

The following agents are all appropriate first-line choices, listed in order of preference based on antimicrobial stewardship principles 1:

• Nitrofurantoin: 100 mg twice daily for 5 days (macrocrystals or monohydrate formulations) 1, 2

  • Preferred because it spares more systemically active agents for other infections 1
  • Achieves high urinary concentrations with minimal impact on vaginal and fecal flora 1

• Fosfomycin trometamol: 3g single dose 1

  • Excellent option for patient convenience and compliance 1
  • Recommended only for women with uncomplicated cystitis 1

• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 3 days 1, 3

  • Use only if local E. coli resistance rates are <20% 1, 4
  • Should not be used if patient had recent exposure to this agent 5

• Pivmecillinam: 400 mg three times daily for 3-5 days 1

  • Where available, this is an excellent first-line option 1

Alternative Second-Line Options

When first-line agents cannot be used 1, 5:

• Cephalosporins (e.g., cefadroxil 500 mg twice daily for 3 days): Only if local E. coli resistance <20% 1
• Fluoroquinolones (e.g., ciprofloxacin): Should be reserved for more serious infections due to resistance concerns and collateral damage to gut microbiome 1, 5, 4
• Beta-lactams (e.g., amoxicillin-clavulanate): Less effective as empirical first-line therapy 4

Treatment for Men

Men with uncomplicated lower UTI require 7 days of treatment 1, 6, 7:

• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 7 days 1, 3
• Nitrofurantoin: 100 mg twice daily for 5-7 days (only if no concern for prostate involvement) 6, 7
• Fluoroquinolones: Preferred if any concern about prostate or upper tract involvement due to better tissue penetration 6

Critical Red Flags That Change Management

Do NOT treat as simple UTI if any of the following are present 1:

• Fever or flank pain: Suggests pyelonephritis, requires different treatment 1
• Pregnancy: Requires different approach entirely 1
• Immunocompromise or diabetes with voiding abnormalities: Consider complicated UTI 1
• Urinary catheter or anatomic abnormalities: Complicated UTI 1
• Age >65 years with frailty or relevant comorbidities: Obtain urine culture before treatment 7
• Vaginal discharge or irritation: Consider alternative diagnosis 1

Diagnostic Approach

For young healthy women with typical symptoms (dysuria, frequency, urgency) and no vaginal symptoms, diagnosis can be made clinically without office visit or urine culture 4, 7:

• Dysuria has >90% accuracy for UTI in young women without vaginal symptoms 1
• Self-diagnosis by women with history of UTI is sufficiently accurate 7

Obtain urine culture with susceptibility testing in these situations 1, 7:

• Recurrent UTIs (≥3 UTIs/year or 2 UTIs in 6 months) 1
• Treatment failure 7
• History of resistant organisms 7
• Atypical presentation 7
• All men with UTI symptoms 7
• Adults ≥65 years 7

Antimicrobial Stewardship Considerations

Avoid fluoroquinolones as first-line empiric therapy 1, 5, 8:

• Increasing resistance rates among community E. coli 5, 4
• Should be reserved for pyelonephritis and complicated infections 1
• Risk of collateral damage to microbiome 6

Consider local resistance patterns 1:

• If local TMP-SMX resistance in E. coli exceeds 20%, choose alternative agent 1, 4
• Regional antibiogram data should guide empiric choices 1

Alternative Management Strategy

Delayed antibiotic treatment with symptomatic management may be considered in low-risk women 7:

• NSAIDs for symptom relief while awaiting culture results 1, 7
• Risk of complications from delayed treatment is low 7
• This approach requires patient counseling and reliable follow-up 7

Common Pitfalls to Avoid

• Do not treat asymptomatic bacteriuria: This is not a UTI and does not require antibiotics 1
• Do not use nitrofurantoin for pyelonephritis: Inadequate tissue levels for upper tract infection 6, 8
• Do not routinely perform cystoscopy or imaging: Not indicated in women <40 years with recurrent UTI and no risk factors 1
• Do not assume all dysuria is UTI in men: Consider urethritis and prostatitis 7