What is the treatment for Candida krusei (Candida krusei) urinary tract infections (UTI)?

Treatment of Candida krusei Urinary Tract Infections

Amphotericin B deoxycholate is the first-line treatment for Candida krusei urinary tract infections, with a dosage of 0.3-0.6 mg/kg daily for 1-7 days. 1

First-Line Treatment Options

• Amphotericin B deoxycholate (0.3-0.6 mg/kg daily for 1-7 days)

  • Achieves high urinary concentrations that exceed MICs for most isolates
  • Even low doses have been shown to be effective in treating Candida UTI 2
  • First-line treatment for C. krusei due to this organism's intrinsic resistance to fluconazole 1, 3

• Amphotericin B bladder irrigation

  • For refractory cystitis: 50 mg/L sterile water daily for 5 days 1
  • Resolves candiduria in 80-90% of patients, though recurrence is common 2
  • Particularly useful for cystitis due to C. krusei when other options fail 2, 4

Important Adjunctive Measures

1. Remove indwelling bladder catheters if present (strongly recommended) 1
2. Eliminate urinary tract obstruction if present 1
3. Remove or replace nephrostomy tubes or stents if feasible 1
4. Discontinue unnecessary antibiotics 1

Treatment Considerations for Special Situations

For Fungus Balls or Obstructions

• Surgical or endoscopic removal of obstructing mycelial mass is essential 2
• Irrigation through nephrostomy tubes with amphotericin B deoxycholate (25-50 mg in 200-500 mL sterile water) 2

For Renal Tissue Invasion

• Echinocandins may be considered despite poor urinary concentrations 2, 1
• Case reports show successful use of micafungin 150 mg daily in transplant patients with chronic symptomatic C. krusei UTI 5

Why Other Antifungals Are Not Recommended

• Fluconazole: C. krusei has intrinsic resistance 2, 3
• Other azoles (voriconazole, posaconazole): Poor urinary concentrations 1
• Lipid formulations of amphotericin B: Do not achieve adequate urine concentrations 2
• Echinocandins: Minimal excretion into urine, generally ineffective for UTI unless renal tissue invasion is present 2
• Flucytosine: C. krusei often has decreased susceptibility; not recommended as monotherapy due to risk of resistance 1, 3

Treatment Duration and Follow-up

• Treat for approximately 2 weeks 1
• Continue until symptoms resolve and urine cultures become negative 1
• Obtain follow-up urine cultures to confirm eradication 1

Common Pitfalls to Avoid

1. Using fluconazole for C. krusei (intrinsic resistance)
2. Using lipid formulations of amphotericin B for lower UTIs
3. Failing to remove indwelling catheters or address underlying conditions
4. Not distinguishing between colonization and true infection
5. Using antifungals with poor urinary concentrations (echinocandins, newer azoles) unless renal tissue invasion is present

Special Considerations for Transplant Patients

In transplant recipients with C. krusei UTI, treatment options may be limited due to drug interactions and toxicity concerns. Higher-dose echinocandins (micafungin 150 mg daily) have been successfully used in case reports despite theoretical limitations 5.