What is the recommended treatment for a 55-year-old female with candiduria (fungal infection of the urine)?

Treatment of Candiduria in a 55-Year-Old Female

Most candiduria represents asymptomatic colonization and does not require antifungal treatment—the priority is removing predisposing factors, particularly indwelling urinary catheters. 1

Initial Assessment: Determine if Treatment is Needed

The critical first step is distinguishing colonization from true infection, as treatment is NOT recommended for asymptomatic candiduria in most patients 1:

• Remove or replace indwelling urinary catheters immediately if present—this alone resolves candiduria in approximately 50% of cases 2, 3
• Eliminate other predisposing factors: discontinue unnecessary broad-spectrum antibiotics, optimize diabetes control, and address any urinary tract obstruction 1, 4
• Observe without treatment unless the patient has symptoms (dysuria, urgency, frequency, flank pain, fever) or belongs to a high-risk group 1

High-Risk Patients Who Require Treatment Despite Asymptomatic Candiduria:

• Neutropenic patients 1
• Very low-birth-weight infants (<1500 g) 1
• Patients undergoing urologic procedures 1

For this 55-year-old woman, treatment is only indicated if she has symptomatic cystitis/pyelonephritis, belongs to a high-risk group, or will undergo urologic manipulation. 1, 2

Treatment Algorithm for Symptomatic Candida UTI

For Symptomatic Cystitis (Lower UTI):

First-line therapy: Oral fluconazole 200 mg daily for 2 weeks 1, 2

• Fluconazole achieves high urinary concentrations in its active form and is effective against most Candida species 2, 5
• The IDSA recommends this as the treatment of choice due to safety, oral availability, and proven effectiveness 2, 6

Alternative for fluconazole-resistant species (C. glabrata, C. krusei):

• Amphotericin B deoxycholate 0.3–0.6 mg/kg daily for 1–7 days 1
• Oral flucytosine 25 mg/kg four times daily for 7–10 days (for C. glabrata) 1

For Symptomatic Pyelonephritis (Upper UTI):

Fluconazole 400 mg daily (after 800 mg loading dose) for 14 days 1, 2

• Higher doses are required for upper tract infections to ensure adequate tissue penetration 2
• Imaging (ultrasound or CT) should be performed to identify obstruction, abscesses, or fungus balls 1, 2

For Patients Undergoing Urologic Procedures:

Prophylactic treatment: Oral 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

Critical Pitfalls to Avoid

• Do NOT use echinocandins (caspofungin, micafungin, anidulafungin) for urinary tract infections—they do not achieve therapeutic urine concentrations and are ineffective 2, 3, 6
• Do NOT use lipid formulations of amphotericin B (liposomal AmB, AmB lipid complex) for isolated lower UTI—they achieve inadequate urinary drug levels 2, 7
• Do NOT use voriconazole or posaconazole for Candida UTI—these azoles have minimal urinary excretion 7, 3
• Do NOT treat asymptomatic candiduria in non-high-risk patients—this leads to unnecessary antifungal exposure, cost, and potential resistance 1, 2
• Failure to remove catheters or relieve obstruction leads to treatment failure regardless of antifungal choice 2

Monitoring and Follow-Up

• Obtain follow-up urine cultures to document clearance of infection 2
• For persistent infection despite appropriate therapy, perform imaging (ultrasound or CT) to identify anatomical abnormalities, hydronephrosis, abscesses, or fungus balls 2
• If fungus balls are present, antifungal therapy alone will not succeed—surgical intervention or percutaneous drainage is required 2, 6

Species-Specific Considerations

While most Candida species are fluconazole-susceptible, resistance patterns matter 1:

• C. albicans, C. parapsilosis, C. tropicalis: Typically fluconazole-susceptible—use standard fluconazole regimen 2
• C. glabrata: Often fluconazole-resistant—use amphotericin B deoxycholate 0.3–0.6 mg/kg daily or flucytosine 1
• C. krusei: Intrinsically fluconazole-resistant—use amphotericin B deoxycholate 0.3–0.6 mg/kg daily 1

Obtain antifungal susceptibility testing if the patient fails initial therapy or if a resistant species is suspected. 5