What is the treatment for a urine culture positive for Candida parapsilosis?

Treatment of Candida parapsilosis Candiduria

For symptomatic Candida parapsilosis urinary tract infections, fluconazole 400 mg daily (after an 800 mg loading dose) for 2 weeks is the first-line treatment, while asymptomatic candiduria typically requires no antifungal therapy. 1

Initial Assessment and Decision to Treat

Determine if treatment is necessary:

• Asymptomatic candiduria does not require antifungal therapy in most patients 1, 2
• Only 4-14% of patients with candiduria have true symptomatic urinary tract infection 2
• Treatment is warranted for: symptomatic cystitis, pyelonephritis, high-risk patients (neutropenic, undergoing urologic procedures), or evidence of disseminated infection 1

Before initiating therapy:

• Obtain a second urine culture to confirm candiduria and exclude contamination 2
• Remove or replace indwelling urinary catheters if present—this alone resolves candiduria in approximately 50% of cases 1, 2
• Eliminate any urinary tract obstruction, which is strongly recommended 1

First-Line Antifungal Treatment

For symptomatic cystitis:

• Fluconazole 400 mg daily (after 800 mg loading dose on day 1) for 7-14 days 1, 2
• Fluconazole achieves high urinary concentrations in its active form and is effective against C. parapsilosis, which is typically fluconazole-susceptible 1, 3
• Oral formulation is acceptable and preferred for ease of administration 1, 4

For pyelonephritis without candidemia:

• Fluconazole 400 mg daily (6 mg/kg/day) for 14 days 1, 2
• If fluconazole resistance is suspected or documented, consider amphotericin B deoxycholate 0.3-0.6 mg/kg daily 1, 2

Alternative and Salvage Therapies

When fluconazole cannot be used:

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily achieves adequate urinary concentrations and is active against C. parapsilosis 1
• For refractory cystitis, amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) can be considered as adjunctive therapy 5

Avoid these agents for isolated urinary tract infections:

• Lipid formulations of amphotericin B do not achieve adequate urine concentrations and should not be used 1, 5
• Echinocandins (caspofungin, micafungin, anidulafungin) have minimal urinary excretion and are generally ineffective for UTI, though they may work for kidney parenchymal infection from hematogenous spread 1
• Other azole agents besides fluconazole fail to achieve adequate urine concentrations 4

Special Considerations for C. parapsilosis

Resistance patterns:

• C. parapsilosis is typically susceptible to fluconazole, amphotericin B, and most antifungals 3
• Fluconazole resistance can emerge with prolonged antifungal exposure and inadequate source control 6
• If treating candidemia with C. parapsilosis, caspofungin shows favorable outcomes and decreased 30-day mortality risk 7, 8

Monitoring and Follow-Up

Essential monitoring steps:

• Obtain follow-up urine cultures to document clearance of infection 5
• For persistent infection despite appropriate therapy, perform imaging (ultrasound or CT) to identify anatomical abnormalities, hydronephrosis, abscesses, or fungus balls 1
• If fungus balls are present, antifungal therapy alone will not be successful—surgical intervention is required 1

Critical Pitfalls to Avoid

• Do not treat asymptomatic candiduria in patients without risk factors for dissemination—removal of catheters and predisposing factors is sufficient 1, 4
• Do not use lipid amphotericin B formulations for isolated lower UTI due to inadequate urinary drug levels 1, 5
• Do not rely on echinocandins for urinary tract infections, as they do not achieve therapeutic urine concentrations 1
• Ensure adequate source control—failure to remove catheters or relieve obstruction leads to treatment failure regardless of antifungal choice 1, 6
• Verify species identification and susceptibility testing if resistance is suspected, particularly with prolonged antifungal exposure 6