How do you treat a complicated Urinary Tract Infection (UTI)?

Treatment of Complicated Urinary Tract Infections

For complicated UTIs with systemic symptoms, use a combination of amoxicillin plus an aminoglycoside, a second-generation cephalosporin plus an aminoglycoside, or an intravenous third-generation cephalosporin as empirical treatment. 1

Initial Assessment and Empiric Therapy

First-line Treatment Options:

• Intravenous therapy options:
  • Amoxicillin plus an aminoglycoside
  • Second-generation cephalosporin plus an aminoglycoside
  • Third-generation cephalosporin (IV)
  • Piperacillin/tazobactam 3.375-4.5g IV every 6 hours 2

Important Considerations for Empiric Therapy:

• Obtain urine culture before initiating antibiotics to confirm causative organism and susceptibility 2
• If catheterized, change indwelling catheter prior to collection if present for more than 2 weeks 2
• Do not use ciprofloxacin and other fluoroquinolones for empirical treatment if:
  • Local resistance rate is ≥10%
  • Patient is from a urology department
  • Patient has used fluoroquinolones in the last 6 months 1

Oral Step-down Therapy

Once clinical improvement occurs and susceptibilities are known, consider step-down to oral therapy:

• Fluoroquinolones (only if local resistance <10%):

  • Ciprofloxacin 500mg twice daily 3
  • Levofloxacin 500mg once daily (adjust for renal function) 2

• Alternative oral options (based on susceptibility):

  • TMP/SMX 160/800mg twice daily (if local resistance <20%) 2
  • Cephalexin 500mg four times daily 2
  • Amoxicillin-clavulanate 500/125mg three times daily 2

Duration of Therapy

• 7-14 days for most complicated UTIs 1, 2
• 10-14 days for patients with delayed response 2
• ≥4-6 weeks for complicated bone and joint infections 3

Special Considerations

Renal Impairment

Adjust dosing based on creatinine clearance:

• Ciprofloxacin dosing:

  • CrCl >50 mL/min: Standard dosing
  • CrCl 30-50 mL/min: 250-500mg q12h
  • CrCl 5-29 mL/min: 250-500mg q18h
  • Hemodialysis/peritoneal dialysis: 250-500mg q24h (after dialysis) 3

• Levofloxacin dosing:

  • CrCl ≥50 mL/min: 500mg once daily
  • CrCl 26-49 mL/min: 500mg once daily
  • CrCl 10-25 mL/min: 250mg once daily 2

Catheter-Associated UTIs

• Treat symptomatic catheter-associated UTIs according to complicated UTI recommendations 1
• Take urine culture before initiating antimicrobial therapy in catheterized patients whose catheter has been removed 1

Antimicrobial Resistance Considerations

For infections with suspected resistant organisms:

• ESBL-producing organisms: Consider carbapenems, ceftazidime-avibactam, or ceftolozane-tazobactam 4
• AmpC β-lactamase producers: Options include nitrofurantoin, fosfomycin, fluoroquinolones (if susceptible), cefepime, piperacillin-tazobactam and carbapenems 4
• Carbapenem-resistant Enterobacteriales: Consider ceftazidime-avibactam, meropenem/vaborbactam, or imipenem/cilastatin-relebactam 4

Management of Urological Abnormalities

• Address any underlying urological abnormality and/or complicating factors 1
• Source control is essential for successful treatment

Urosepsis Management

For patients presenting with urosepsis (life-threatening organ dysfunction from dysregulated host response to infection):

• Immediate broad-spectrum antibiotic coverage
• Prompt source control
• Monitor using Sequential Organ Failure Assessment (SOFA) score or quick SOFA (qSOFA) 1, 2

Common Pitfalls to Avoid

1. Fluoroquinolone overuse: Avoid empiric use when local resistance rates exceed 10% or in patients with recent fluoroquinolone exposure 1
2. Inadequate duration: Shorter courses may be insufficient for complicated infections
3. Failure to obtain cultures: Always collect specimens before starting antibiotics
4. Neglecting source control: Addressing anatomical abnormalities is crucial for cure
5. Overlooking renal function: Dose adjustments are essential in renal impairment

By following these evidence-based recommendations, clinicians can effectively manage complicated UTIs while minimizing the risk of treatment failure and antimicrobial resistance.