What is the treatment for a fungal urinary tract infection (UTI) caused by yeast?

Treatment of Yeast in Urine (Fungal UTI)

Fluconazole is the drug of first choice for treating fungal urinary tract infections, at a dose of 200-400 mg (3-6 mg/kg) daily for 2 weeks for most cases of yeast in urine. 1

Diagnostic Approach

Before initiating treatment, it's important to distinguish between asymptomatic candiduria and symptomatic infection:

• Asymptomatic candiduria in most patients does not require treatment except in:
  • Neutropenic patients
  • Very low-birth-weight infants
  • Patients undergoing urologic procedures 2
• Symptomatic infection requires treatment based on the site of infection (cystitis vs. pyelonephritis)

Treatment Algorithm

1. For Candida Cystitis (Lower UTI)

• First-line: Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
• For fluconazole-resistant C. glabrata:
  • AmB deoxycholate 0.3-0.6 mg/kg daily for 1-7 days, with or without oral flucytosine (25 mg/kg 4 times daily) 1
  • Alternative: Monotherapy with oral flucytosine 25 mg/kg 4 times daily for 2 weeks 1
• For C. krusei infections:
  • AmB deoxycholate 0.3-0.6 mg/kg daily for 1-7 days 1

2. For Candida Pyelonephritis (Upper UTI)

• First-line: Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
• For fluconazole-resistant strains:
  • AmB deoxycholate 0.5-0.7 mg/kg daily with or without flucytosine (25 mg/kg 4 times daily) for 2 weeks 1
  • Alternative: Flucytosine alone at 25 mg/kg 4 times daily for 2 weeks 1

3. For Fungus Balls

• Surgical intervention is strongly recommended in adults 1
• Antifungal treatment as noted above for cystitis or pyelonephritis 1
• If nephrostomy tubes are present, irrigation with AmB deoxycholate (25-50 mg in 200-500 mL sterile water) 1

Special Considerations

Refractory Cases

For persistent candiduria despite appropriate antifungal therapy:

• Evaluate for structural abnormalities or obstruction
• Consider bladder irrigation with AmB deoxycholate (50 mg/L sterile water) for refractory cystitis due to resistant organisms like C. glabrata and C. krusei 1

Important Caveats

1. Catheter management: Remove or replace indwelling catheters if possible, as this alone may resolve candiduria in up to 50% of cases 3

2. Drug selection considerations:

   • Lipid formulations of AmB do not achieve adequate urine concentrations and should not be used 1
   • Newer azoles (except fluconazole) and echinocandins have minimal excretion into urine and are generally ineffective 1, 3
   • Echinocandins may be considered for renal parenchymal infections despite poor urinary concentrations 1

3. Treatment duration: Continue treatment until symptoms have resolved and urine cultures no longer yield Candida species 1

4. Diagnostic pitfalls: Colony count in urine, especially with catheters present, cannot reliably differentiate infection from colonization 1

By following this treatment algorithm and considering the specific Candida species and site of infection, most fungal urinary tract infections can be successfully treated, reducing morbidity and improving quality of life.