What is the recommended treatment for a patient with a Candida infection of the urine?

Treatment of Candida Urinary Tract Infections

Initial Critical Decision: Treat or Observe?

Most patients with asymptomatic candiduria do not require antifungal treatment—observation alone is appropriate after eliminating predisposing factors such as removing urinary catheters. 1, 2

However, treatment is mandatory in these high-risk populations:

• Neutropenic patients (treat as systemic candidemia, not isolated UTI) 1, 2
• Very low-birth-weight neonates 1, 2
• Patients undergoing urologic procedures or manipulation 1, 2
• Symptomatic patients with cystitis or pyelonephritis 1, 2

Treatment Algorithm for Symptomatic Candida Cystitis

For fluconazole-susceptible species (most C. albicans), oral fluconazole 200 mg daily for 14 days is the first-line treatment. 1, 2, 3 A loading dose of 400 mg on day 1 may be considered per FDA labeling. 3 Recent evidence suggests that shorter durations (7 days median) may achieve equivalent clinical success rates (93.1% vs 93.3%, P=1.000), though this requires further validation. 4

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

• Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days 1, 2
• Alternative: Oral flucytosine 25 mg/kg four times daily for 7-10 days (monitor for toxicity and resistance development) 1, 2
• Amphotericin B bladder irrigation is generally not recommended due to high relapse rates, but may be considered for resistant species when systemic therapy fails 1

Treatment Algorithm for Candida Pyelonephritis

For fluconazole-susceptible organisms, oral fluconazole 200-400 mg (3-6 mg/kg) daily for 14 days is recommended. 1, 5, 2 The higher dose (400 mg) should be used for more severe infections or immunocompromised hosts. 5

For fluconazole-resistant species (C. glabrata):

• Amphotericin B deoxycholate 0.5-0.7 mg/kg IV daily with or without flucytosine 25 mg/kg four times daily for 14 days 1, 5, 2
• Flucytosine monotherapy 25 mg/kg four times daily is an alternative if amphotericin B cannot be used 1

Critical adjunctive measure: Elimination of urinary tract obstruction is essential for treatment success—failure to address anatomical issues will result in treatment failure regardless of antifungal choice. 5 Remove or replace nephrostomy tubes and stents whenever feasible. 5

Prophylaxis for Urologic Procedures

Patients with candiduria undergoing urologic manipulation require prophylactic antifungal therapy to prevent dissemination. 1, 5, 2

Recommended regimens:

• Fluconazole 200-400 mg (3-6 mg/kg) daily for several days before and after the procedure 1, 5
• Alternative: Amphotericin B deoxycholate 0.3-0.6 mg/kg daily 1, 5

Special Populations and Situations

Neutropenic patients and low-birth-weight neonates must be treated as having systemic candidemia, not isolated UTI—use echinocandins or liposomal amphotericin B at systemic doses per candidemia guidelines. 1, 2 For neonates specifically, amphotericin B deoxycholate 1 mg/kg daily is recommended, with fluconazole 12 mg/kg daily as an alternative if not on fluconazole prophylaxis. 1

Fungus balls require surgical or endoscopic intervention in addition to systemic antifungal therapy. 1, 2 Medical therapy alone is insufficient. Fluconazole 200-400 mg daily or amphotericin B 0.5-0.7 mg/kg daily with or without flucytosine should be continued until symptoms resolve and urine cultures clear. 1 If access to the renal collecting system is available, irrigation with amphotericin B 50 mg/L sterile water can be used as an adjunct. 1

Key Clinical Pitfalls

Fluconazole is the only azole that achieves therapeutic urinary concentrations—other azoles (voriconazole, posaconazole, isavuconazole) have minimal urinary excretion and should not be used for isolated urinary candidiasis. 1, 6, 7

Echinocandins do not achieve reliable urinary concentrations and their role in Candida UTI remains unclear, with both successes and failures reported in small case series. 6 They should be reserved for systemic infections or when treating high-risk populations as candidemia. 1, 2

Catheter removal alone resolves candiduria in approximately 50% of cases—this should be the first management step before initiating antifungal therapy in asymptomatic patients. 8

Monitoring and Follow-up

Follow-up urine cultures should document eradication after treatment completion. 2 For patients receiving amphotericin B, monitor renal function and electrolytes closely. 1 For flucytosine, monitor complete blood counts and hepatic function due to potential bone marrow suppression and hepatotoxicity. 1