The Unexpected and Troubling Rise of Candida auris

Tom Chiller, MD


August 24, 2017

Editorial Collaboration

Medscape &

Hello. I am Dr Tom Chiller, chief of the Mycotic Diseases Branch at the Centers for Disease Control and Prevention (CDC). As part of the CDC Expert Commentary Series on Medscape, I would like to tell you about Candida auris, a novel yeast that is behaving in unexpected and concerning ways, causing severe disease in countries across the globe, including the United States. Today we'll share how you can protect your patients from this potentially deadly infection, the history of this unusual bug, and how the United States is working with global partners to combat its spread.

Several features set C auris apart from other Candida species and make it a particular concern:

  1. C auris can spread between patients in healthcare facilities and cause outbreaks. In this way, it appears to behave much like some multidrug-resistant bacteria (eg, methicillin-resistant Staphylococcus aureus or Acinetobacter). Using contact precautions to prevent transmission may sound strange for Candida, but for C auris, they are a key part of the control strategy.

  2. C auris can colonize a patient's skin for months or longer. It can be readily detected by culturing swabs of a colonized patient's axilla, groin, or other body sites. In light of this, use of contact precautions, as well as strict attention to hand hygiene, are critical elements in controlling spread. CDC is also working with partners to better understand the role of topical agents to prevent spread by reducing colonization.

  3. This hardy yeast can live on surfaces for a month or more, and preliminary testing suggests that quaternary ammonium compounds commonly used for healthcare disinfection may not be sufficiently effective against C auris. Until further testing is available, CDC recommends that healthcare facilities meticulously perform daily and terminal cleaning of rooms of patients who were infected or colonized with C auris with an EPA-registered disinfectant that is effective against Clostridium difficile spores.

  4. C auris is quickly becoming more common. In some international healthcare facilities, it has gone from an unknown pathogen to a cause of 40% of invasive Candida infections within a few years. We need to act now to prevent this from happening in the United States.

  5. C auris is often multidrug resistant. Some strains have been resistant to all three major antifungal classes, including echinocandins, the first-line treatment for Candida infections.

  6. C auris has reportedly never been isolated from the natural environment, and it does not seem to have been a common colonizer of humans before 2009. More research is needed to understand where in the environment C auris lives and why it began affecting humans only recently.

CDC's website has the most up-to-date guidance on identifying, treating, and controlling the spread of C auris. In healthcare facilities, including nursing homes and outpatient settings, the key measures are to:

  • Place patients in single rooms and use standard and contact precautions.

  • Emphasize adherence to hand hygiene, including use of alcohol-based hand rubs.

  • Clean the patient care environment with recommended disinfectants.

  • Screen patients to identify C auris colonization, and report suspected cases to local public health authorities and to CDC immediately for guidance. C auris can be misidentified using traditional methods. CDC and the Antibiotic Resistance Regional Laboratories can assist with identification and characterization.

Background: Candida

Candida species are a leading cause of healthcare-associated bloodstream infections in the United States and internationally.[1] Most invasive Candida infections are thought to result from autoinfection with the host's own yeast flora during microbiome disruption—for example, from broad-spectrum antibiotic therapy, or from an invasive device like a central line.[2] Accordingly, outbreaks of Candida infections have been rare, because little evidence of transmission existed.

Of the more than 400 named Candida species, only a few dozen regularly cause human infections.[3] In 2009, a new Candida species, called C auris, was reported, having been isolated from the ear canal of a woman in Japan.[4] By 2016, C auris had been identified in several other countries in various regions of the world. To understand how it spread so quickly, CDC worked with partners in several countries to gather C auris isolates and test them by whole-genome sequencing.

The results were surprising and puzzling. A single strain of C auris was not spreading around the world, nor were many unrelated strains suddenly being recognized. Instead, isolates fell into four distinct clades (groups) along geographic lines.[5] It appeared that distinct strains had emerged nearly simultaneously in four different regions of the world. Changes in the environment may have led to its emergence, followed by subsequent transmission in healthcare settings.

Cases in the United States were soon identified. Retrospective reviews of hospital microbiology records found very few cases identified before 2016, suggesting that C auris is still new in the United States. CDC worked closely with health departments and healthcare facilities to respond to the first cases, learning more about how this organism spreads and how to stop it.[6] Cases had occurred primarily in people with extensive healthcare exposure, including those in long-term care facilities.

Visit CDC's website on Candida auris for updated case counts and locations. Thank you for watching. Together, we can control the spread of this new and concerning pathogen.

Web Resources

EPA-Registered Disinfectant List

CDC: Candida auris: