Treatment of Candida parapsilosis Urinary Tract Infection
For Candida parapsilosis UTI, oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks is the recommended first-line treatment due to its excellent urinary penetration and C. parapsilosis susceptibility profile. 1
Diagnostic Considerations
Before initiating treatment, it's important to distinguish between true infection and colonization:
- Pyuria and colony counts are not reliable indicators of infection when catheters are present
- Imaging (ultrasound or CT) is helpful to identify structural abnormalities, hydronephrosis, or fungus balls
- Symptoms of cystitis or pyelonephritis support true infection versus asymptomatic colonization
Treatment Algorithm
First-line therapy:
- Fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
- Fluconazole achieves high urinary concentrations
- C. parapsilosis shows high susceptibility to fluconazole (93% efficacy) 2
- Available in both oral and intravenous formulations
Alternative therapies (if fluconazole cannot be used):
Amphotericin B deoxycholate 0.3-0.6 mg/kg/day IV for 1-7 days 1, 3
- Effective but has toxicity concerns and requires IV administration
- Monitor renal function closely
Liposomal amphotericin B 3-5 mg/kg/day IV 1
- For severe infections or fluconazole-resistant isolates
- Less nephrotoxic than conventional amphotericin B
Adjunctive measures (critical for successful treatment):
- Remove indwelling bladder catheter if present (strong recommendation) 1
- Correct any urinary tract obstruction (strong recommendation) 1
- Consider surgical intervention for fungus balls 1
Special Situations
Fluconazole-resistant C. parapsilosis:
- Uncommon but possible scenario
- Amphotericin B deoxycholate 0.3-0.6 mg/kg/day IV for 1-7 days 1
- Consider amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) for cystitis 1
Severe infection or pyelonephritis:
- Treat as candidemia with systemic therapy 1
- Consider longer duration of therapy (>2 weeks)
Treatment Duration and Monitoring
- Treat for 2 weeks after symptom resolution 1
- Obtain follow-up urine cultures to document clearance
- Monitor for clinical improvement of symptoms
Important Caveats
- Echinocandins (caspofungin, micafungin, anidulafungin) have minimal urinary excretion and are generally ineffective for UTIs despite in vitro activity 1, 4
- Lipid formulations of amphotericin B do not achieve adequate urine concentrations for UTI treatment 1
- Voriconazole and other azoles (except fluconazole) have minimal urinary excretion and are not recommended 1, 4
- C. parapsilosis infections may be more complicated than other Candida species and might require more aggressive treatment 5
By following this treatment approach focusing on fluconazole as first-line therapy and addressing any underlying factors like catheter removal or obstruction, most C. parapsilosis UTIs can be effectively treated with minimal complications.