Candida auris
Small yeasts, without obvious pseudohyphae
Identification & Growth
Identification
- Germ tube-negative; CHROMagar Candida Plus shows a pale colony with a blue halo
- Identification requires MALDI-TOF with an updated database — biochemical systems misidentify it as C. haemulonii
Growth Conditions
- Grows at 42 °C and in high salinity; Sabouraud agar 35–37 °C, 24–48 h
Clinical Significance
- Candidemia and skin/axillary colonization in the ICU; hospital outbreaks
Intrinsic Resistance
- Fluconazole resistance is frequent; a subset of isolates is resistant to amphotericin B and echinocandins
Bench Alerts
- Mandatory notification and immediate contact precautions
- Always perform antifungal susceptibility testing and notify infection control
Clinical Notes
Clinical presentations
- Candidemia and catheter-associated invasive infection, with high lethality in critically ill patients.
- Persistent colonization of skin (axilla and groin), nares and rectum, which sustains environmental transmission.
- Urinary, wound and device infection, whose interpretation requires distinguishing colonization from disease.
Specimens and collection
- Blood culture for invasive disease; a combined axilla-groin swab is the standard colonization screening method.
- Screen bed contacts and patients transferred from facilities with known cases.
- Collect environmental samples from near-patient surfaces during outbreak investigation.
Epidemiology and at-risk populations
- Emerging pathogen with hospital spread, classified by WHO in the critical priority group of fungal pathogens.
- It survives for weeks on dry surfaces and resists low-level disinfectants, requiring validated sporicidal products.
- Highest risk with ICU stay, mechanical ventilation, central catheter, parenteral nutrition and prior antifungal use.
Resistance and therapeutic implications
- Fluconazole resistance is the rule in most isolates; amphotericin B and echinocandin resistance occur less often.
- An echinocandin is the recommended initial therapy while susceptibility testing is pending.
- Always request antifungal susceptibility testing and repeat it if fungemia persists.
Bench and reporting notes
- Older biochemical systems misidentify it as C. haemulonii, C. famata or Rhodotorula: confirm by MALDI-TOF with an updated database.
- It grows at 42 °C and in high salinity, and most strains form neither germ tube nor true pseudohyphae.
- An immediately notifiable finding: alert infection control, start contact precautions and flag the case in the medical record.
Sources
- CDC — Candida auris
- WHO — Fungal priority pathogens list
- EUCAST — Antifungal susceptibility testing (AFST)
Educational decision-support content. It does not replace laboratory validation, current guidelines or review by the responsible professional.
FAQ: Frequently Asked Questions
How to identify Candida auris in the lab?
Candida auris is identified through germ tube-negative; chromagar candida plus shows a pale colony with a blue halo, identification requires maldi-tof with an updated database — biochemical systems misidentify it as c. haemulonii.
What are the intrinsic resistances of Candida auris?
This organism is naturally resistant to fluconazole resistance is frequent; a subset of isolates is resistant to amphotericin b and echinocandins. These drugs should not be reported as susceptible.
Where is Candida auris commonly found?
It is typically associated with candidemia and skin/axillary colonization in the icu; hospital outbreaks.
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