What is the recommended treatment for candida urinary tract infection (UTI) in patients with indwelling ureteral stents?

Treatment of Candida UTI with Indwelling Ureteral Stents

For patients with candida UTI and indwelling ureteral stents, removal or replacement of the stent is strongly recommended, along with appropriate antifungal therapy based on susceptibility testing, with fluconazole being the preferred agent for susceptible species. 1

Initial Management Approach

1. Evaluate necessity of stent removal/replacement:

   • Removal or replacement of ureteral stents should be considered whenever feasible 1
   • Biofilms form readily on stents and catheters, making eradication of infection without device removal/replacement difficult 1

2. Determine Candida species and susceptibility:

   • Obtain urine culture with susceptibility testing before initiating therapy
   • Species identification is critical as treatment differs for fluconazole-resistant species

Antifungal Treatment Algorithm

For Fluconazole-Susceptible Candida Species (most C. albicans):

• First-line therapy: Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
• Fluconazole achieves high urine concentrations and is effective against biofilm-associated infections 2

For Fluconazole-Resistant C. glabrata:

• Option 1: Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
• Option 2: Amphotericin B deoxycholate with oral flucytosine 25 mg/kg 4 times daily 1
• Alternative: Monotherapy with oral flucytosine 25 mg/kg 4 times daily for 2 weeks 1

For C. krusei:

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1

Timing of Stent Management

• Initiate antifungal therapy 48 hours to 3 weeks before stent removal/replacement 3
• This approach helps sterilize urine and prevents recolonization of new stents

Local Therapy Options

• For persistent infections with fluconazole-resistant species:
  • Amphotericin B deoxycholate bladder irrigation (50 mg/L sterile water daily for 5 days) may be useful 1
  • For renal pelvis infections with fungus balls, irrigation through nephrostomy tubes with Amphotericin B deoxycholate (25-50 mg in 200-500 mL sterile water) is recommended 1

Important Considerations and Pitfalls

1. Avoid echinocandins and newer azoles for UTIs:

   • These agents achieve inadequate urine concentrations despite their activity against Candida biofilms 2, 4
   • The exception may be severe infections where these agents are used systemically in combination with local therapy or stent removal

2. Duration of therapy:

   • Continue treatment for at least 2 weeks for uncomplicated infections 1
   • Longer therapy may be needed for complicated infections

3. Monitoring:

   • Follow-up urine cultures to confirm eradication
   • Monitor for systemic spread in high-risk patients

4. Prevention strategies:

   • Regular stent changes every 3-6 months in high-risk patients 3
   • Minimize unnecessary antibiotic exposure

5. Common pitfall: Treating asymptomatic candiduria in patients without risk factors for dissemination

   • Treatment is NOT recommended unless the patient is neutropenic, a very low-birth-weight infant, or undergoing urologic manipulation 1

By following this approach, focusing on stent management and appropriate antifungal therapy, most candida UTIs associated with ureteral stents can be effectively treated while minimizing complications and recurrence.