What is the drug of choice for a Urinary Tract Infection (UTI) caused by Candida tropicalis?

Drug of Choice for Candida tropicalis UTI

Oral fluconazole at a dosage of 200 mg daily for 2 weeks is the drug of choice for urinary tract infections caused by Candida tropicalis. 1

Treatment Algorithm for C. tropicalis UTI

First-line Treatment

• Fluconazole 200 mg (3 mg/kg) daily for 2 weeks for susceptible C. tropicalis 1
• Fluconazole achieves high urinary concentrations, making it ideal for treating Candida UTIs 1, 2
• FDA-approved for Candida urinary tract infections 3

For Fluconazole-Resistant C. tropicalis

If resistance to fluconazole is documented or treatment failure occurs:

1. Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1
2. Flucytosine 25 mg/kg 4 times daily for 7-10 days (alternative) 1

For Upper Tract Infection (Pyelonephritis)

• Fluconazole 200-400 mg daily for 2 weeks for susceptible strains 1
• For resistant strains: Amphotericin B deoxycholate 0.5-0.7 mg/kg daily with or without flucytosine 1

Evidence Strength and Considerations

Fluconazole has demonstrated good efficacy against C. tropicalis specifically, with studies showing an 82% response rate for C. tropicalis infections 4. This is significantly better than the response rate for other non-albicans species like C. glabrata (50%) 4.

The Infectious Diseases Society of America guidelines strongly support fluconazole as first-line therapy for Candida UTIs due to its:

• High urinary concentrations
• Availability in both oral and IV formulations
• Favorable safety profile 1, 5

Important Adjunctive Measures

• Remove indwelling urinary catheters if present (resolves ~50% of cases) 1, 2
• Discontinue unnecessary antibiotics 1
• Address any urinary tract obstruction 1
• Obtain follow-up urine cultures to confirm eradication 1

Common Pitfalls to Avoid

1. Using inappropriate antifungals: Echinocandins (caspofungin, micafungin, anidulafungin) and newer azoles (voriconazole, posaconazole) should not be used for uncomplicated Candida UTIs due to poor urinary concentrations 1, 6

2. Treating asymptomatic candiduria: Treatment is generally not recommended unless the patient belongs to a high-risk group (neutropenic patients, very low-birth-weight infants, patients undergoing urologic procedures) 1, 2

3. Using flucytosine as monotherapy: This can lead to rapid development of resistance 1

4. Using lipid formulations of amphotericin B: These should be avoided for lower UTIs due to inadequate urinary concentrations 1

5. Failure to distinguish between colonization and infection: Most cases of candiduria represent colonization rather than true infection, especially in catheterized patients 2, 5

For fungus balls or abscesses, surgical intervention is strongly recommended in addition to systemic antifungal therapy 1.