How should I treat an adult urinary tract infection with Candida (fungal) involvement, especially if the patient has dysuria, flank pain, fever and risk factors such as an indwelling catheter, diabetes, immunosuppression, or recent broad‑spectrum antibiotics?

Treatment of Urinary Tract Infection with Candida

For symptomatic fungal UTI with dysuria, flank pain, and fever in a patient with risk factors (catheter, diabetes, immunosuppression, or recent antibiotics), immediately remove the indwelling catheter if present and initiate oral fluconazole 200–400 mg daily for 14 days, adjusting based on Candida species susceptibility and whether infection involves the bladder (cystitis) or kidney (pyelonephritis). 1, 2

Initial Critical Management Steps

Remove the indwelling catheter immediately if one is present—this single intervention clears candiduria in approximately 40–50% of cases without any antifungal therapy and is the most common cause of treatment failure when not performed. 1, 2, 3

• Eliminate any urinary tract obstruction, and consider removing or replacing nephrostomy tubes or ureteral stents if feasible. 1
• Obtain urine culture to identify the specific Candida species and determine fluconazole susceptibility, as this directly impacts treatment selection. 1

Treatment Algorithm Based on Clinical Presentation and Species

For Symptomatic Cystitis (Lower UTI)

Fluconazole-susceptible species (C. albicans, C. tropicalis, C. parapsilosis):

• Fluconazole 200 mg (3 mg/kg) orally once daily for 14 days is first-line therapy. 1, 2, 3
• Fluconazole achieves excellent urinary concentrations of active drug, making it the preferred agent for most Candida UTIs. 3, 4

Fluconazole-resistant C. glabrata:

• Amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days OR oral flucytosine 25 mg/kg four times daily for 7–10 days. 1, 5
• C. glabrata represents approximately 20% of urinary isolates and is frequently fluconazole-resistant. 5
• Amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) may be useful for resistant cystitis. 1

C. krusei (intrinsically fluconazole-resistant):

• Amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days. 1

For Symptomatic Pyelonephritis (Upper UTI with Flank Pain/Fever)

Fluconazole-susceptible organisms:

• Fluconazole 200–400 mg (3–6 mg/kg) orally once daily for 14 days—use the higher 400 mg dose when upper tract involvement is confirmed. 1, 2, 3

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
• Oral flucytosine 25 mg/kg four times daily for 14 days as monotherapy may be considered when amphotericin B is unsuitable, though this is a weaker recommendation. 1

C. krusei:

• Amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days. 1

Special Considerations for High-Risk Patients

Immunocompromised Patients

• Treat all immunocompromised patients with candiduria due to risk of disseminated disease, even if minimally symptomatic. 2
• For severely immunocompromised patients with fever and candiduria, consider an echinocandin (caspofungin 70 mg loading then 50 mg daily, micafungin 100 mg daily, or anidulafungin 200 mg loading then 100 mg daily) as preferred therapy due to concern for systemic candidiasis. 2
• If systemic candidiasis is suspected, treat with an echinocandin for at least 2 weeks after blood cultures clear. 2

Neutropenic Patients

• Treat as candidemia regardless of symptoms—follow candidemia treatment protocols. 1, 2

Patients with Renal Impairment

• Reduce fluconazole dose by 50% if creatinine clearance is significantly impaired. 2
• Monitor creatinine and electrolytes closely with amphotericin B therapy. 2

Critical Pitfalls to Avoid

Do not use echinocandins as first-line therapy for urinary Candida infections—they achieve inadequate urinary concentrations, have limited clinical data, and documented therapeutic failures in this setting. 5, 4

Do not rely on colony counts or pyuria to distinguish colonization from infection in catheterized patients, as these are unreliable indicators. 3

Do not overlook the possibility of disseminated candidiasis in high-risk patients (immunosuppressed, diabetic, catheterized) presenting with candiduria and fever—obtain blood cultures and consider broader evaluation. 2, 3

Do not treat empirically without considering species identification—approximately 15–20% of urinary Candida isolates are C. glabrata (often fluconazole-resistant) and C. krusei is intrinsically fluconazole-resistant. 5, 6

Monitoring and Follow-Up

• Repeat urine culture 1–2 weeks after completing therapy to document mycological clearance. 3
• For patients with persistent candiduria despite appropriate therapy, evaluate for urinary tract obstruction, fungal balls, or occult upper tract involvement requiring surgical intervention. 1, 7
• Address underlying risk factors: discontinue unnecessary broad-spectrum antibiotics, optimize diabetes control, and minimize immunosuppression when feasible. 3, 8

Controversial Evidence: Empiric Antifungals in Critically Ill Patients

Important caveat: While IDSA guidelines recommend empiric antifungal therapy for critically ill patients with risk factors for invasive candidiasis 1, a large retrospective study of 18,496 septic patients found that empiric antifungal therapy in ICU patients with positive yeast cultures and urinary tract infection was actually associated with increased in-hospital mortality (OR = 3.24,95% CI: 1.48–7.11, p = 0.003) and did not improve outcomes. 1 This suggests that routine empiric antifungal therapy should be avoided in urinary candidiasis unless the patient has septic shock or specific high-risk features warranting treatment. 1