What is the recommended treatment for a patient with a urinary tract infection caused by yeast, considering their medical history and potential underlying conditions?

Treatment of Yeast in Urinalysis

Most patients with yeast in the urine (candiduria) do NOT require antifungal treatment unless they are symptomatic, neutropenic, very low-birth-weight infants, or undergoing urologic procedures. 1

Initial Management: Risk Stratification

First, determine if treatment is actually needed:

• Asymptomatic candiduria requires NO treatment in immunocompetent patients, as this typically represents colonization or contamination 1, 2
• Remove predisposing factors first - this alone clears candiduria in approximately 50% of cases 1, 3, 4:
  • Remove indwelling urinary catheters if feasible 1, 2
  • Discontinue unnecessary broad-spectrum antibiotics 3
  • Confirm candiduria with a second urine culture to rule out contamination 5

High-risk patients who DO require treatment even if asymptomatic 1, 2:

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

Treatment Algorithm for Symptomatic Infections

Candida Cystitis (Bladder Infection)

For fluconazole-susceptible species (most C. albicans):

• Oral fluconazole 200 mg (3 mg/kg) daily for 2 weeks 1, 2, 5
• Mandatory catheter removal if present 1, 2

For fluconazole-resistant C. glabrata:

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1, 2
• OR oral flucytosine 25 mg/kg four times daily for 7-10 days 1, 2
• Amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) may be used as adjunctive therapy for resistant organisms, but has high relapse rates when used alone 1, 2

For C. krusei:

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1, 2

Candida Pyelonephritis (Kidney Infection)

For fluconazole-susceptible species:

• Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1, 2, 5
• Eliminate urinary tract obstruction - remove or replace nephrostomy tubes/stents if feasible 1, 2

For fluconazole-resistant C. glabrata:

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days with or without flucytosine 25 mg/kg four times daily 1, 2, 5
• Flucytosine monotherapy (25 mg/kg four times daily for 2 weeks) is a weaker alternative 1, 2

Fungus Balls

• Surgical intervention is strongly recommended 1, 2
• Systemic antifungal therapy: Fluconazole 200-400 mg (3-6 mg/kg) daily OR Amphotericin B deoxycholate 0.5-0.7 mg/kg daily with or without flucytosine 1, 2
• Local irrigation with Amphotericin B through nephrostomy tubes can be used as adjunctive therapy 1, 2

Prophylaxis for Urologic Procedures

For patients with candiduria undergoing urologic manipulation:

• Oral fluconazole 400 mg (6 mg/kg) daily for several days before and after the procedure 1, 2
• OR Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for several days before and after the procedure 1, 2

Critical Clinical Pitfalls

Avoid these common errors:

• Do NOT treat asymptomatic candiduria in immunocompetent patients - this leads to unnecessary antifungal exposure, potential toxicity, and promotes resistance 2, 6, 3
• Catheter removal is as important as antifungal therapy - failure to remove catheters significantly reduces treatment success 1, 2, 4
• Echinocandins and newer azoles (except fluconazole) do NOT achieve adequate urine concentrations and should not be used for urinary tract infections 6, 3, 4
• Bladder irrigation alone has high relapse rates and should only be used as adjunctive therapy for refractory resistant organisms 1, 2, 4

Why Fluconazole is Preferred

Fluconazole is the antifungal of choice for Candida UTIs because:

• Achieves high urinary concentrations with oral formulation 6, 3, 4
• Available in both oral and intravenous formulations 4
• Excellent safety profile 4
• Broad activity against most Candida species 3