What is the recommended treatment for an uncomplicated urinary tract infection (UTI) in an adult?

Treatment of Uncomplicated UTI in Adults

For uncomplicated lower urinary tract infection (cystitis) in adult women, first-line treatment is nitrofurantoin 100 mg twice daily for 5 days, fosfomycin 3 g single dose, or trimethoprim-sulfamethoxazole 160/800 mg twice daily for 3 days (only if local E. coli resistance is <20%). 1, 2

First-Line Treatment Options for Women with Uncomplicated Cystitis

The WHO and European Association of Urology guidelines prioritize the following agents based on efficacy, resistance patterns, and minimal "collateral damage" (selection of multidrug-resistant organisms): 1, 2

• Nitrofurantoin: 100 mg twice daily for 5 days (monohydrate/macrocrystals formulation) 1, 2, 3

  • Remains highly active against drug-resistant uropathogens with low resistance rates 4
  • Minimal collateral damage compared to fluoroquinolones 5

• Fosfomycin trometamol: 3 g single oral dose 1, 2, 6

  • Convenient single-dose therapy 6
  • Should be mixed with water before ingesting, never taken in dry form 6

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

  • Only use if local E. coli resistance rates are below 20% 2, 5
  • Increasing resistance has limited its first-line status in many regions 5

Alternative Second-Line Options

When first-line agents are contraindicated or unavailable: 2, 7

• Cephalosporins (e.g., cefadroxil 500 mg twice daily for 3 days) if local E. coli resistance <20% 2
• Trimethoprim alone: 200 mg twice daily for 5 days (avoid in first trimester of pregnancy) 2

Treatment for Men with Uncomplicated UTI

Men require longer treatment duration—7 days instead of 3-5 days: 2, 3

• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 7 days 2
• Nitrofurantoin: 100 mg twice daily for 7 days 3
• Trimethoprim: 200 mg twice daily for 7 days 3
• Always obtain urine culture and susceptibility testing in men 3

Treatment for Uncomplicated Pyelonephritis (Upper UTI)

For mild-to-moderate pyelonephritis requiring outpatient oral therapy: 1

• 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

For severe pyelonephritis requiring hospitalization: 1

• Ceftriaxone or cefotaxime (intravenous): 1-2 g daily 1
• Amikacin (intravenous): 15 mg/kg daily for severe cases 1

Critical Prescribing Considerations

Avoid fluoroquinolones for simple cystitis: 1, 2, 5

• Reserve ciprofloxacin and levofloxacin for pyelonephritis or complicated infections 1, 5
• Fluoroquinolones cause significant collateral damage by selecting multidrug-resistant organisms 5
• FDA warnings exist regarding tendon, muscle, joint, nerve, and CNS adverse effects 1

Do not use amoxicillin or ampicillin empirically: 2

• High prevalence of antimicrobial resistance makes these ineffective 2

Resistance thresholds matter: 2, 5

• Trimethoprim-sulfamethoxazole should only be used when local E. coli resistance is documented <20% 2, 5
• If patient received these antibiotics recently, resistance risk increases significantly 5

Diagnosis Without Office Visit

Women with typical symptoms (dysuria, frequency, urgency, suprapubic pain) and no vaginal discharge can be diagnosed and treated without urine culture: 2, 3, 8

Urine culture IS required for: 2, 3

• Suspected pyelonephritis 2
• Symptoms persisting or recurring within 4 weeks after treatment 2
• Atypical symptoms 2
• Pregnant women 2
• All men with UTI symptoms 3
• Treatment failures 2

Treatment Failures

If symptoms persist after initial therapy: 2

• Obtain urine culture and susceptibility testing 2
• Retreat with a different agent for 7 days based on culture results 2

Special Populations

Women with diabetes: 8

• Treat similarly to women without diabetes if no voiding abnormalities present 8
• Use same first-line agents and durations 8

Adults ≥65 years: 3

• Obtain urine culture with susceptibility testing 3
• Use same first-line antibiotics and durations as younger adults 3

What NOT to Do

Do not treat asymptomatic bacteriuria (except in pregnant women or before urologic procedures): 1, 2

• Strong evidence shows no benefit in non-pregnant adults 1
• Omit surveillance urine testing in asymptomatic patients 1

Do not routinely obtain post-treatment cultures in asymptomatic patients: 2

• Follow-up cultures only needed if symptoms persist or recur within 2-4 weeks 2