Information for Laboratory Staff

Candida auris: A drug-resistant yeast that spreads in healthcare facilities

Early detection can help limit spread of C. auris

Candida auris is a yeast that causes serious infections. Infection preventionists, healthcare workers, and laboratory staff can all help stop it from spreading.

Why is Candida auris a problem?

  • It causes serious infections. C. auris can cause bloodstream and other types of invasive infections, particularly in patients in hospitals and nursing homes who have multiple medical problems. More than 1 in 3 patients die within a month of C. auris infection.
  • It is often multidrug-resistant. Antifungal medications commonly used to treat Candida infections often don’t work for C. auris. Some C. auris isolates are resistant to all three major classes of antifungal medications.
  • It’s becoming more common. Although C. auris was just recognized in 2009, it has emerged quickly. Since then, it has been reported from over 20 countries, including the United States.
  • It’s difficult to identify. C. auris can be misidentified as other types of yeast unless specialized laboratory methods are used. Unrecognized C. auris can spread to other patients in a facility, causing an outbreak. Identifying C. auris is critical to knowing what steps to take to control it in a healthcare setting.
  • It can spread in healthcare facilities. Just like other multidrug-resistant organisms such as CRE and MRSA, C. auris can be transmitted in healthcare settings and cause outbreaks. It can colonize patients for many months, persist in the environment, and withstand many routinely used disinfectants in healthcare facilities.

Prepare for C. auris identification

  1. Some phenotypic methods for yeast identification can misidentify C. auris as a number of different organisms.
    • C. auris is most often misidentified as Candida haemulonii, another rare yeast, but misidentifications are specific to each yeast identification method.
    • Know whether the yeast identification method used in your laboratory misidentifies C. auris and, if so, what the possible misidentifications are.
      See common misidentifications by yeast identification method.
    • Misidentification can lead to inappropriate patient treatment and delay implementation of appropriate infection control precautions.
  2. There are no phenotypic characteristics that can easily distinguish C. auris from other Candida species.
  3. The most reliable way to identify C. auris is matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).
    • If you have a MALDI-TOF MS, ensure C. auris is included in the database.
  4. Molecular methods based on DNA sequencing can also identify C. auris. Sequencing of the D1-D2 region of the 28s ribosomal DNA (rDNA) or internal transcribed spacer (ITS) region of rDNA are accepted methods.
  5. Validate your instrument to confirm it can identify C. auris. If needed, use isolates from the CDC & FDA Antibiotic Resistance Isolate Bank.
  6. Work with your facility’s infection preventionist to set up a plan for informing their department about possible or confirmed C. auris and subsequent notification of public health authorities.
  7. Work with your state and local public health department for further characterization of these isolates. The health department will determine whether additional outreach to the Antibiotic Resistance Laboratory Network or CDC is needed.

lab worker holding up c.auris specimens

More guidance on when to suspect C. auris, how to correctly identify C. auris, and suggested antifungal drug minimum inhibitory concentration (MIC) cutoff values are available on CDC’s webpage, Recommendations for Identification of C. auris.

What should I do if C. auris is confirmed?

  1. Report possible or confirmed C. auris cases immediately to your facility’s infection prevention and control department and follow your facility’s process for reporting to public health.
  2. Conduct antifungal susceptibility testing.
  3. Look for other cases of C. auris in your facility:
    • Review microbiology records back to 2015 if possible to find potentially missed cases.
    • Begin surveillance for C. auris from clinical specimens to identify new cases.
      • C. auris is found in many body sites and fluids, including blood, urine, respiratory, and abdominal specimens.
      • Consider identifying the species of Candida isolates from both sterile and non-sterile sites, even if this is not routine practice at your facility. Continue this surveillance for at least one month or until there is no evidence of transmission.