Treatment of Candida tropicalis UTI
For symptomatic Candida tropicalis urinary tract infection, fluconazole 200 mg (3 mg/kg) orally daily for 2 weeks is the treatment of choice, as C. tropicalis is typically fluconazole-susceptible with demonstrated 82% efficacy. 1, 2
Initial Assessment and Management Approach
Before initiating antifungal therapy, determine whether treatment is actually indicated:
- Asymptomatic candiduria does NOT require treatment unless the patient is neutropenic, a very low-birth-weight infant, or undergoing urologic procedures 1, 3
- Remove or replace urinary catheters if present, as elimination of predisposing factors alone resolves candiduria in approximately 50% of cases 1, 4
- Distinguish between cystitis and pyelonephritis through clinical presentation and imaging if needed, as this affects dosing 1
Treatment Regimens by Clinical Presentation
For Symptomatic Cystitis (Lower UTI)
Primary therapy:
- Fluconazole 200 mg (3 mg/kg) orally daily for 2 weeks 1
- A loading dose of 200 mg followed by 100 mg daily for at least 4 days is an alternative supported by pharmacokinetic data 5
- Fluconazole is preferred because it achieves high urinary concentrations in its active form and is available orally 1, 6
Alternative therapy (if fluconazole cannot be used):
- Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days 1, 3
- Oral flucytosine 25 mg/kg four times daily for 7-10 days (use with caution due to toxicity and resistance development) 1, 6
For Pyelonephritis (Upper UTI)
Primary therapy:
- Fluconazole 200-400 mg (3-6 mg/kg) orally daily for 2 weeks 1
- The higher dose range (400 mg) is appropriate for more severe upper tract infections 1
Alternative therapy:
- Amphotericin B deoxycholate 0.5-0.7 mg/kg IV daily with or without flucytosine 25 mg/kg four times daily for 2 weeks 1
For Patients Undergoing Urologic Procedures
Even if asymptomatic, prophylactic treatment is warranted:
- Fluconazole 200-400 mg (3-6 mg/kg) daily OR amphotericin B deoxycholate 0.3-0.6 mg/kg daily for several days before and after the procedure 1, 7
Why Fluconazole Works for C. tropicalis
- C. tropicalis demonstrates 82% treatment success with fluconazole in clinical studies, making it reliably susceptible 2
- Fluconazole was the only agent proven effective in a randomized, double-blind, placebo-controlled trial for candiduria 1
- It achieves urinary concentrations that far exceed the MIC for most C. tropicalis isolates 1, 6
Critical Pitfalls to Avoid
Do NOT use these agents for C. tropicalis UTI:
- Echinocandins (caspofungin, micafungin, anidulafungin) achieve minimal urinary concentrations and are generally ineffective for lower UTI, though they may work for renal parenchymal infections 1, 7, 4
- Other azoles (voriconazole, posaconazole, itraconazole) have minimal active drug excretion in urine 1, 4
- Lipid formulations of amphotericin B do not achieve adequate urine concentrations and should not be used 1, 7
Do NOT rely on colony counts or pyuria to differentiate colonization from infection, especially with indwelling catheters—these tests cannot reliably distinguish the two 1, 7
Bladder irrigation with amphotericin B resolves candiduria in 80-90% initially but has very high recurrence rates and is generally discouraged except for refractory fluconazole-resistant cystitis 1, 7
Special Considerations
Imaging is indicated if:
- Treatment failure occurs despite appropriate therapy 1
- Suspicion exists for fungus balls, hydronephrosis, abscesses, or structural abnormalities 1
- Fungus balls require surgical intervention in addition to antifungal therapy 1
Duration of therapy: