Treatment of Complicated UTI in Females
For a female with a complicated UTI, obtain a urine culture before initiating empiric antibiotic therapy, then start treatment based on severity, local resistance patterns, and prior culture data if available, using fluoroquinolones (if local resistance <10%) or parenteral agents for severe cases, with culture-directed adjustment once susceptibilities return. 1
Critical First Step: Proper Classification
Avoid misclassifying patients as having "complicated" UTI, as this leads to unnecessary broad-spectrum antibiotic use. 2 Reserve the complicated UTI designation for patients with:
- Congenital or acquired structural/functional urinary tract abnormalities
- Obstruction at any urinary tract site
- Foreign bodies or indwelling catheters
- Incomplete voiding or vesicoureteral reflux
- Immunosuppression or pregnancy
- Recent instrumentation
- Healthcare-associated infections
- ESBL-producing or multidrug-resistant organisms 2, 1
Diagnostic Requirements
Always obtain urine culture and susceptibility testing before initiating antibiotics for complicated UTIs. 2, 1 This is essential for:
- Confirming the diagnosis
- Guiding definitive therapy
- Tracking resistance patterns
- Assessing treatment response if symptoms persist 2
Empiric Antibiotic Selection
For Hemodynamically Stable Patients (Uncomplicated Pyelonephritis)
First-line empiric options include: 1
Fluoroquinolones (if local resistance <10%):
Extended-spectrum cephalosporins:
- Ceftriaxone 1-2 g IV once daily 1
Extended-spectrum penicillins with aminoglycosides 1
Aminoglycosides:
- Gentamicin 5 mg/kg IV once daily 1
For Complicated UTI with Systemic Symptoms
Use combination parenteral therapy: 1
- Amoxicillin plus aminoglycoside, OR
- Second-generation cephalosporin plus aminoglycoside, OR
- Third-generation cephalosporin IV 1
Oral Step-Down Therapy
Once the patient is hemodynamically stable and afebrile, transition to oral therapy: 1
- Ciprofloxacin 500-750 mg PO twice daily (7 days total) 1
- Levofloxacin 750 mg PO once daily (5 days total) 1, 3
- Trimethoprim-sulfamethoxazole 160/800 mg twice daily (14 days total) 1
- Cefpodoxime 200 mg twice daily (10 days total) 1
- Ceftibuten 400 mg once daily (10 days total) 1
Treatment Duration
Standard duration is 7 days for most complicated UTIs. 1 However:
- Extend to 14 days in men when prostatitis cannot be excluded 1
- For complicated UTI/pyelonephritis in women: 7-14 days 1
- Levofloxacin 750 mg daily has demonstrated efficacy with a 5-day regimen for complicated UTI and acute pyelonephritis 3
Culture-Directed Therapy Adjustment
Narrow antibiotic spectrum based on susceptibility results. 1 Key considerations:
- Tailor to the specific pathogen and its resistance profile
- Consider consultation with infectious disease specialists for resistant organisms 1
- Account for local antibiogram data 2
- Consider patient allergies, side effects, and cost 2
Critical Pitfalls to Avoid
Do NOT treat asymptomatic bacteriuria in women with complicated UTI, as this fosters antimicrobial resistance and increases recurrent infection episodes. 2 Exceptions are pregnant women and patients before invasive urologic procedures. 1
If symptoms persist despite treatment, repeat urine culture to assess for ongoing bacteriuria before prescribing additional antibiotics. 2
Avoid prolonged antibiotic courses (>5-7 days for lower tract, >14 days for upper tract) and unnecessary broad-spectrum antibiotics, as these disrupt normal vaginal and fecal flora and promote resistance. 2
Antimicrobial Stewardship Principles
Prioritize agents with minimal collateral damage to normal flora: 2
- Use nitrofurantoin when possible for re-treatment, as resistance is low and decays quickly if present 2
- Prefer nitrofurantoin, trimethoprim-sulfamethoxazole, or trimethoprim over fluoroquinolones and cephalosporins for prophylaxis 2
- Reserve fluoroquinolones for severe infections or when first-line agents are contraindicated 2, 1