What is the management of urinary tract infections (UTIs) in females, including dosage and duration of antibiotics, and how to proceed when there is no response to initial treatment, particularly in pregnant women?

Management of Urinary Tract Infections in Females and Pregnancy

For uncomplicated UTIs in females, first-line treatment includes nitrofurantoin (100 mg BID for 5 days), fosfomycin (3g single dose), or trimethoprim-sulfamethoxazole (160/800 mg BID for 3 days) based on local resistance patterns. 1

Diagnosis and Initial Assessment

• Obtain urinalysis and urine culture with sensitivity testing before initiating treatment for recurrent UTIs 1
• Urine culture is specifically recommended in:
  • Suspected pyelonephritis
  • Symptoms that don't resolve or recur within 4 weeks after treatment
  • Women with atypical symptoms
  • Pregnant women 1
• Patient-initiated treatment (self-start) may be offered to select patients with recurrent UTIs while awaiting culture results 1

Treatment Regimens for Uncomplicated Cystitis in Women

First-line options:

• Fosfomycin trometamol: 3g single dose (1 day) 1, 2
• Nitrofurantoin macrocrystals: 50-100 mg four times daily for 5 days 1
• Nitrofurantoin monohydrate/macrocrystals: 100 mg twice daily for 5 days 1
• Pivmecillinam: 400 mg three times daily for 3-5 days 1

Alternative options:

• Cephalosporins (e.g., cefadroxil): 500 mg twice daily for 3 days (if local E. coli resistance <20%) 1
• Trimethoprim: 200 mg twice daily for 5 days (avoid in first trimester of pregnancy) 1
• Trimethoprim-sulfamethoxazole: 160/800 mg twice daily for 3 days (avoid in last trimester of pregnancy) 1, 3

Treatment Duration

• For uncomplicated cystitis: Short courses as specified above 1
• For recurrent UTI patients with acute episodes: Generally no longer than 7 days 1
• For complicated or resistant infections: 7-day regimen with an agent different from initial treatment 1

Special Considerations for Pregnancy

• Avoid trimethoprim in the first trimester of pregnancy 1
• Avoid trimethoprim-sulfamethoxazole in the last trimester of pregnancy 1
• Obtain urine culture in all pregnant women with suspected UTI 1
• Safe options during pregnancy (after first trimester) include:
  • Nitrofurantoin (avoid near term)
  • Cephalosporins
  • Amoxicillin-clavulanate (based on susceptibility) 4, 5

Management of Treatment Failure

• If symptoms don't resolve by the end of treatment or recur within 2 weeks:
  • Perform urine culture and antimicrobial susceptibility testing 1
  • Assume the infecting organism is not susceptible to the original agent 1
  • Retreat with a 7-day regimen using a different antibiotic 1
• For infections resistant to oral antibiotics:
  • Use culture-directed parenteral antibiotics for as short a course as reasonable (generally ≤7 days) 1
  • Consider local resistance patterns when selecting alternative agents 4

Recurrent UTIs Management

• Diagnose recurrent UTI via urine culture 1
• Consider non-antimicrobial interventions first:
  • Increased fluid intake for premenopausal women 1
  • Vaginal estrogen replacement for postmenopausal women 1
  • Immunoactive prophylaxis 1
  • Methenamine hippurate 1
• For antimicrobial prophylaxis (when non-antimicrobial interventions fail):
  • Continuous or post-coital antimicrobial prophylaxis 1
  • Self-administered short-term antimicrobial therapy for patients with good compliance 1

Antibiotic Stewardship Considerations

• Avoid fluoroquinolones for uncomplicated UTIs due to unfavorable risk-benefit ratio 1
• Beta-lactams are not considered first-line therapy due to collateral damage effects and tendency to promote more rapid recurrence 1
• Do not treat asymptomatic bacteriuria except in pregnant women 1
• Avoid surveillance urine testing in asymptomatic patients with recurrent UTIs 1

Pitfalls and Caveats

• Increasing antibiotic resistance necessitates knowledge of local susceptibility patterns 4, 6
• Fluoroquinolones should be restricted due to adverse effects and increasing resistance 5
• Avoid treating asymptomatic bacteriuria as it increases risk of symptomatic infection, bacterial resistance, and healthcare costs 1
• Longer courses or broader-spectrum antibiotics are not needed for recurrent UTIs and may disrupt protective microbiota 1
• For persistent or recurrent infections, consider structural or functional abnormalities of the urinary tract 1