Treatment of Yeast in the Urine
For symptomatic Candida urinary tract infections, oral fluconazole 200-400 mg daily for 2 weeks is the first-line treatment for fluconazole-susceptible species. 1
Initial Assessment: Infection vs. Colonization
Before initiating treatment, you must distinguish true infection from colonization:
- Treat if symptomatic (dysuria, frequency, urgency, fever, flank pain) or if the patient falls into high-risk categories requiring treatment 2, 3
- Do NOT treat asymptomatic candiduria in most patients, as candidemia occurs in <5% of cases and removal of predisposing factors often clears the infection 3, 4
- High-risk patients requiring treatment even if asymptomatic: neutropenic patients, low birth weight infants, patients undergoing urologic procedures, severely immunocompromised patients with fever, and those with urinary tract obstruction 3
Critical first step: Remove or replace indwelling urinary catheters if present, as this alone resolves candiduria in approximately 50% of cases 3, 5
Treatment Algorithm by Clinical Scenario
For Symptomatic Cystitis (Lower UTI)
First-line for fluconazole-susceptible species (most C. albicans):
- Fluconazole 200-400 mg (3-6 mg/kg) orally daily for 2 weeks 1, 2
- Fluconazole is preferred because it achieves high urinary concentrations in active form and is available orally 1
For fluconazole-resistant C. glabrata:
- Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days, with or without oral flucytosine 25 mg/kg four times daily 1, 2
- Alternative: Flucytosine monotherapy 25 mg/kg orally four times daily for 2 weeks (weaker recommendation) 1
For C. krusei:
For Pyelonephritis (Upper UTI)
For fluconazole-susceptible organisms:
For resistant species:
- Amphotericin B deoxycholate 0.5-0.7 mg/kg/day with or without flucytosine 6
For Patients Undergoing Urologic Procedures
- Fluconazole 200-400 mg (3-6 mg/kg) daily for several days before and after the procedure 3
Essential Structural Management
Always address anatomic issues concurrently with antifungal therapy:
- Eliminate urinary tract obstruction (strong recommendation) 1
- Remove or replace nephrostomy tubes or stents if feasible 1
- Fungus balls require surgical or endoscopic removal in addition to antifungal therapy, as antifungals alone will fail 1
- Consider irrigation through nephrostomy tubes with amphotericin B deoxycholate 25-50 mg in 200-500 mL sterile water if tubes are present 1
Critical Pitfalls to Avoid
Do NOT use these agents for Candida UTI:
- Echinocandins (caspofungin, micafungin, anidulafungin) achieve minimal urinary concentrations and are generally ineffective 1, 2, 5
- Lipid formulations of amphotericin B do not achieve adequate urine concentrations 1, 2
- Other azoles besides fluconazole (voriconazole, posaconazole, isavuconazole) have poor urinary excretion 1, 2
Avoid bladder irrigation with amphotericin B except in specific circumstances:
- While it resolves candiduria in 80-90% initially, recurrence within weeks is very common 1
- Only useful for bladder infections, not upper tract disease 1
- Generally discouraged, especially in patients who don't otherwise need a catheter 1
Do NOT treat asymptomatic candiduria in patients without risk factors, as this provides no benefit and promotes resistance 2, 3
Species-Specific Considerations
- C. albicans (most common, ~60% of isolates): typically fluconazole-susceptible and easiest to treat 1, 6
- C. glabrata: often fluconazole-resistant, requiring amphotericin B or flucytosine 1
- C. krusei: intrinsically fluconazole-resistant, requires amphotericin B 1, 7