Treatment of Candida krusei Infection
For invasive C. krusei infections including candidemia, an echinocandin (caspofungin, micafungin, or anidulafungin) is the preferred first-line therapy, with voriconazole reserved as step-down oral therapy once the patient is clinically stable. 1, 2
Initial Therapy for Invasive C. krusei/Candidemia
First-Line Treatment: Echinocandins
- Caspofungin: 70 mg loading dose on day 1, then 50 mg daily 1, 2
- Micafungin: 100 mg daily 1, 2
- Anidulafungin: 200 mg loading dose on day 1, then 100 mg daily 1, 2
The echinocandins are strongly recommended as initial therapy because C. krusei exhibits intrinsic resistance to fluconazole and variable susceptibility to amphotericin B 1, 3. The 2016 IDSA guidelines specifically identify echinocandins as the preferred agents for C. krusei candidemia 1, 2.
Alternative First-Line Options
Amphotericin B deoxycholate: 0.5-1.0 mg/kg daily, or lipid formulation amphotericin B 3-5 mg/kg daily if echinocandins cannot be used 1, 2
Voriconazole: 400 mg (6 mg/kg) IV twice daily for 2 doses, then 200 mg (3 mg/kg) twice daily can be used when additional mold coverage is desired 1
Step-Down Therapy
Voriconazole is recommended as step-down oral therapy for selected cases of C. krusei candidemia once the patient is clinically stable, at a dose of 400 mg twice daily for 2 doses, then 200 mg twice daily 1, 2, 5. This transition should only occur after clinical improvement and documented bloodstream clearance 1, 2.
Essential Adjunctive Measures
- Remove central venous catheters as early as possible when the source is presumed to be the catheter 1, 2
- Perform follow-up blood cultures daily or every other day to establish when candidemia has cleared 1, 2
- Continue treatment for 2 weeks after documented clearance from bloodstream and resolution of symptoms 1, 2
- Perform dilated ophthalmological examination within the first week after diagnosis in all non-neutropenic patients 1, 2
Treatment of C. krusei Urinary Tract Infections
Assessment
First, determine whether the infection represents true symptomatic infection requiring treatment versus asymptomatic candiduria 6, 2. Treatment is warranted for symptomatic patients and high-risk groups (neutropenic patients, very low birth-weight infants, patients undergoing urologic manipulation) 6, 2.
First-Line UTI Treatment
- Amphotericin B deoxycholate: 0.3-0.6 mg/kg daily for 1-7 days 6, 2
- Alternative for cystitis: Amphotericin B deoxycholate bladder irrigation, 50 mg/L sterile water daily for 5 days 6, 2
Alternative UTI Treatment
- Micafungin: 150 mg daily has been successfully used for chronic symptomatic C. krusei UTI in transplant recipients, despite traditionally poor urinary concentrations of echinocandins 7
UTI Management Principles
- Remove indwelling bladder catheter if present 6, 2
- Eliminate any urinary tract obstruction 6, 2
- Duration: 2 weeks for both cystitis and pyelonephritis 6, 2
- Repeat urine cultures to document clearance 6, 2
Special Populations
Neutropenic Patients
The treatment algorithm remains the same with echinocandins as first-line therapy, though catheter removal should be performed rapidly regardless of species 2.
Neonates
Amphotericin B deoxycholate is preferred due to low toxicity in this population and lack of pharmacokinetic data for echinocandins 2.
Critical Pitfalls to Avoid
- Never use fluconazole for C. krusei infections—this species exhibits intrinsic resistance 1, 3, 7
- Do not assume amphotericin B susceptibility—some isolates demonstrate resistance 2, 3
- Avoid azole cross-resistance—approximately 5.5% of C. krusei strains may show high MICs to all azoles including voriconazole 4
- Do not use standard echinocandin doses for UTI—consider higher doses (e.g., micafungin 150 mg) or alternative agents like amphotericin B that achieve better urinary concentrations 7