What is the recommended treatment for a Citrobacter (C.) koseri urinary tract infection in an adult male?

Treatment of Citrobacter koseri Urinary Tract Infection in Adult Males

For Citrobacter koseri urinary tract infections in adult males, fluoroquinolones (ciprofloxacin 500-750 mg BID for 7 days) are recommended as first-line therapy, provided local resistance rates are below 10%. 1

Diagnostic Approach

• Obtain urine culture before initiating antibiotic therapy to confirm the causative organism and determine susceptibility patterns 1
• Consider Citrobacter koseri UTI as a complicated UTI in males, as male gender is a complicating factor 1
• Evaluate for underlying urological abnormalities that may complicate treatment 1

First-Line Treatment Options

• Ciprofloxacin 500-750 mg twice daily for 7 days (if fluoroquinolone resistance <10%) 1
• Levofloxacin 750 mg once daily for 5 days (alternative fluoroquinolone option) 1

Alternative Treatment Options (Based on Susceptibility)

• Trimethoprim-sulfamethoxazole 160/800 mg twice daily for 14 days 1
• Cefpodoxime 200 mg twice daily for 10 days 1
• Ceftibuten 400 mg once daily for 10 days 1
• For multidrug-resistant strains, consider:
  • Aminoglycosides (gentamicin 5 mg/kg daily or amikacin 15 mg/kg daily) 1
  • Carbapenems (meropenem 1g three times daily) 1, 2

Treatment Duration

• 7 days for patients with prompt symptom resolution 1
• 10-14 days for patients with delayed response 1
• 14 days when prostatitis cannot be excluded in male patients 1

Special Considerations

• C. koseri has inherent resistance to ampicillin, requiring careful antibiotic selection 3, 2
• For catheter-associated UTI caused by C. koseri:
  • Replace the catheter if it has been in place for ≥2 weeks 1
  • Obtain a new urine culture from the freshly placed catheter 1
• Consider local resistance patterns when selecting empiric therapy 4
• Emerging resistance to beta-lactams and aminoglycosides may necessitate carbapenem therapy in some cases 3, 2

Monitoring and Follow-up

• Assess clinical response within 72 hours of treatment initiation 1
• If symptoms persist beyond 72 hours, consider:
  • Extending treatment duration to 10-14 days 1
  • Urological evaluation for anatomical abnormalities 1
  • Alternative antibiotics based on susceptibility testing 1

Potential Complications

• C. koseri can cause serious infections beyond UTI, including bloodstream infections and endocarditis in rare cases 3, 5
• Monitor for signs of systemic infection, especially in immunocompromised patients 6, 2

Prevention

• Remove urinary catheters as soon as clinically appropriate to reduce risk of catheter-associated infections 1
• Address any underlying urological abnormalities that may predispose to recurrent infections 1