Treatment of Candida lusitaniae UTI (50,000-99,000 CFU/mL)
For symptomatic Candida lusitaniae UTI, treat with oral fluconazole 200 mg (3 mg/kg) daily for 2 weeks, as this organism is typically fluconazole-susceptible and this regimen achieves excellent urinary concentrations. 1, 2
Initial Clinical Assessment
Determine if treatment is indicated based on patient risk factors:
- Asymptomatic candiduria does NOT require treatment unless the patient is neutropenic, a very low-birth-weight infant (<1500 g), or undergoing urologic procedures 1, 3
- Colony counts of 50,000-99,000 CFU/mL cannot reliably differentiate colonization from infection, especially with indwelling catheters present 4
- Remove or replace urinary catheters immediately if feasible, as this alone resolves candiduria in approximately 50% of cases 3, 5
Treatment Algorithm for Symptomatic Infection
First-Line Therapy
For cystitis (lower UTI):
- Fluconazole 200 mg (3 mg/kg) orally daily for 2 weeks 1, 2, 6
- This achieves high urinary concentrations and has proven 82% efficacy 7
For pyelonephritis (upper UTI):
- Fluconazole 200-400 mg (3-6 mg/kg) orally daily for 2 weeks 1, 3
- Use the higher dose (400 mg) for more severe upper tract infections 7
Alternative Therapy (if fluconazole cannot be used)
C. lusitaniae is typically fluconazole-susceptible, but if resistance is documented:
- Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days 1, 3
- Flucytosine 25 mg/kg orally 4 times daily for 7-10 days 1, 3
Critical Management Considerations
Address anatomical factors:
- Eliminate urinary tract obstruction as this is critical for treatment success 2
- Remove or replace nephrostomy tubes or stents if feasible 2, 4
- Obtain imaging (CT or ultrasound) if treatment fails despite appropriate therapy to rule out fungus balls, hydronephrosis, or abscesses 2, 7
Special population: Patients undergoing urologic procedures:
- Treat prophylactically with fluconazole 400 mg (6 mg/kg) daily OR amphotericin B deoxycholate 0.3-0.6 mg/kg daily for several days before and after the procedure 1, 3
Important Pitfalls to Avoid
Do NOT use echinocandins (caspofungin, micafungin, anidulafungin) for lower urinary tract infections, as they achieve minimal urinary concentrations and are ineffective for Candida UTI 2, 4, 5
Do NOT use lipid formulations of amphotericin B (liposomal amphotericin, amphotericin B lipid complex), as they do not achieve adequate urine concentrations 2
Do NOT use voriconazole, posaconazole, or itraconazole for UTI treatment, as these azoles fail to achieve sufficient urinary levels 4, 5
Avoid amphotericin B bladder irrigation as it has 80-90% initial success but high recurrence rates and is generally discouraged 4, 8
C. lusitaniae-Specific Considerations
C. lusitaniae has unique characteristics that influence treatment:
- Generally susceptible to fluconazole, making it the preferred agent 9
- Historically known for amphotericin B resistance, though this varies 10, 9
- Forms biofilms on catheters and cardiac valves, making catheter removal essential 10
- Can cause disseminated infection from urinary sources, particularly with indwelling catheters 10
Monitoring and Duration
Continue treatment until:
- Symptoms have completely resolved 2, 7
- Urine cultures no longer yield Candida species 2, 4
- Standard duration is 2 weeks for uncomplicated cystitis 1, 2
Obtain follow-up urine cultures to confirm clearance of infection 2
If persistent infection occurs despite appropriate therapy, obtain imaging to evaluate for fungus balls or structural abnormalities that may require surgical intervention 2, 7