Treatment of Non-Candida Yeast UTI
For urinary tract infections caused by non-Candida yeasts (such as Cryptococcus, Rhodotorula, Trichosporon, or Saccharomyces), amphotericin B deoxycholate 0.5-0.7 mg/kg daily is the primary treatment, as fluconazole and other azoles have unreliable activity against these organisms. 1
Initial Assessment and Species Identification
- Obtain definitive species identification through culture and susceptibility testing, as non-Candida yeasts have vastly different antifungal susceptibility patterns compared to Candida species 1
- Remove or replace indwelling urinary catheters immediately if present, as this alone can resolve fungal colonization in approximately 50% of cases 2, 3
- Evaluate for predisposing conditions including diabetes mellitus, broad-spectrum antibiotic use, urinary obstruction, and immunosuppression 4
Treatment Algorithm by Clinical Presentation
Symptomatic Cystitis (Lower UTI)
- Amphotericin B deoxycholate 0.5-0.7 mg/kg IV daily is the treatment of choice for non-Candida yeast cystitis, as most non-Candida yeasts are not reliably susceptible to fluconazole 1
- Flucytosine 25 mg/kg four times daily can be added for synergy, particularly for Cryptococcus species, though resistance can develop when used alone 1, 2
- Continue treatment until symptoms resolve and urine cultures no longer yield the organism 1
Pyelonephritis (Upper UTI)
- Amphotericin B deoxycholate 0.5-0.7 mg/kg IV daily with or without flucytosine 25 mg/kg four times daily is recommended for upper tract infections 1
- Higher doses of amphotericin B (up to 0.7 mg/kg) should be used for severe pyelonephritis to ensure adequate tissue penetration 1
- If percutaneous access to the renal collecting system is available, adjunctive irrigation with amphotericin B at 50 mg/L in sterile water can be considered 1
Fungus Balls or Obstructive Disease
- Aggressive surgical debridement is essential for fungus balls anywhere in the urinary collecting system, as antifungal therapy alone is insufficient 1
- Systemic amphotericin B deoxycholate (with or without flucytosine) should be combined with surgical intervention 1
- If nephrostomy tubes provide direct access, local irrigation with amphotericin B can be used as adjunctive therapy 1
Critical Pitfalls to Avoid
- Do not use fluconazole empirically for non-Candida yeasts, as organisms like Cryptococcus neoformans, Rhodotorula species, and Trichosporon species often have reduced susceptibility or frank resistance to azoles 1, 4
- Avoid echinocandins and lipid formulations of amphotericin B for urinary tract infections, as they achieve inadequate urinary concentrations and have documented treatment failures 1, 2
- Do not treat asymptomatic colonization unless the patient is neutropenic, a very low-birth-weight infant, or undergoing urologic procedures 5, 2
Species-Specific Considerations
- Cryptococcus neoformans: Requires amphotericin B plus flucytosine combination therapy, similar to CNS cryptococcosis protocols, given the potential for disseminated disease 1
- Rhodotorula species: Intrinsically resistant to echinocandins and often resistant to azoles; amphotericin B is the only reliable option 1
- Trichosporon species: Variable azole susceptibility; amphotericin B remains first-line until susceptibilities are confirmed 1
Monitoring and Follow-Up
- Obtain follow-up urine cultures to document clearance of infection after completing therapy 6, 2
- Perform imaging (ultrasound or CT) if infection persists despite appropriate therapy to identify anatomical abnormalities, hydronephrosis, or fungus balls 5, 6
- Monitor renal function and electrolytes closely during amphotericin B therapy due to nephrotoxicity risk 1