What is the first-line treatment for a man diagnosed with an Extended-Spectrum Beta-Lactamase (ESBL) Urinary Tract Infection (UTI)?

First-Line Treatment for ESBL UTI in Men

For men diagnosed with Extended-Spectrum Beta-Lactamase (ESBL) Urinary Tract Infection (UTI), intravenous meropenem 2g every 8 hours is the recommended first-line treatment. 1

Treatment Algorithm

Initial Assessment

• Confirm ESBL UTI diagnosis through:
  • Urinalysis showing moderate to large leukocytes and positive nitrites
  • Urine culture with 50,000-100,000 CFU/mL of gram-negative bacilli
  • Antimicrobial susceptibility testing confirming ESBL production

Treatment Options

First-line Treatment:

• Intravenous Meropenem: 2g every 8 hours 1
  • Duration: 10-14 days for uncomplicated UTI
  • Duration: 21 days for complicated UTI or if bacteremia is present 1, 2

Alternative Parenteral Options (based on susceptibility):

• Imipenem/cilastatin-relebactam
• Ceftazidime-avibactam
• Ceftolozane-tazobactam
• Aminoglycosides (e.g., Amikacin) 2, 3

Oral Step-down Options (if susceptible):

• Fosfomycin: 3g single dose or every 10 days for complicated cases 2, 4
• Nitrofurantoin: 100mg twice daily for 7-14 days (only for lower UTI) 3, 4
• Pivmecillinam (if available and susceptible) 4

Clinical Considerations

Severity Assessment

• For severely ill patients or those with signs of systemic infection:
  • Start with parenteral therapy
  • Consider hospitalization for initial management
  • Assess for complications such as prostatitis or pyelonephritis

Monitoring

• Clinical response should be assessed within 48-72 hours of starting treatment
• If symptoms persist beyond 72 hours:
  • Repeat urine culture
  • Consider changing antibiotic based on culture results
  • Evaluate for complications or anatomical abnormalities 2

Special Considerations for Men

• Longer treatment duration is typically required compared to women
• Higher risk of complicated UTI due to anatomical factors
• Consider prostate involvement (prostatitis) which requires extended therapy

Evidence Strength and Rationale

The recommendation for meropenem as first-line therapy is based on high-quality guideline evidence 1 that specifically addresses ESBL organisms. The UK Joint Specialist Societies guideline explicitly states: "If there is a high suspicion that an extended spectrum beta lactamase (ESBL) organism might be present IV Meropenem 2 g 8 hourly should be given."

Recent research supports this approach, with studies showing that carbapenems remain highly effective against ESBL-producing organisms 3, 5. While some studies suggest potential oral alternatives like fosfomycin and nitrofurantoin for uncomplicated cases 4, these should be considered only after susceptibility is confirmed and for less severe infections.

Pitfalls to Avoid

1. Fluoroquinolone use: Despite historical use, high resistance rates now preclude fluoroquinolones as empiric therapy for ESBL UTIs 3, 5

2. Inadequate treatment duration: Men typically require longer treatment courses (10-21 days) compared to women with uncomplicated UTIs 2

3. Ignoring local resistance patterns: Treatment should always be guided by local antimicrobial sensitivity patterns 2

4. Failure to adjust for renal function: Most antibiotics require dose adjustments based on creatinine clearance 2

5. Missing prostate involvement: Male UTIs frequently involve the prostate, requiring extended therapy and follow-up 6