Candida auris Clinical Update - September 2017

Candida auris is an emerging, multidrug-resistant yeast that causes invasive infections and is transmitted in healthcare settings. This notice for clinicians, laboratorians, and public health officials updates a June 2016 clinical alert with important information from investigations of U.S. cases of C. auris. These investigations have been done by state and local public health agencies in collaboration with CDC.  As of August 31, 2017, a total 153 clinical cases of C. auris infection have been reported to CDC from 10 U.S. states; most have occurred in New York and New Jersey. An additional 143 patients have been found to be colonized with C. auris based on targeted screening.

CDC is notifying healthcare providers and laboratories of the following findings from ongoing collaborative investigations of U.S. cases.

• U.S. hospitals have identified C. auris in patients who were recently hospitalized in other countries. Five U.S. cases were identified in patients who had recent hospitalizations in countries with known C. auris transmission (India, Pakistan, South Africa, and Venezuela). C. auris was isolated from urine or wound cultures from these patients. Based on whole genome sequencing and epidemiologic information, most other U.S. cases likely resulted from local transmission of C. auris following previous introduction from other countries.
• Patients have been infected or colonized with C. auris in wounds, urine, sputum, and other non-invasive sites. Because many clinical laboratories do not determine the species of Candida for isolates from these sites, C. auris colonization may go unrecognized and lead to transmission. About 54% of recognized U.S. clinical cases have been identified from blood cultures. The remaining patients with positive C. auris cultures, including those with recent hospitalizations abroad, have had the organism isolated from other body sites, including skin wounds, urine, respiratory specimens, bile fluid, and ears.  Determining the species of Candida for isolates from these non-invasive sites in certain situations may allow for more rapid identification of C. auris and allow for timely implementation of targeted infection control measures to reduce transmission.
• Patients have been persistently colonized with C. auris, posing long-term risk of transmission. Patients with C. auris infection have been persistently colonized. Close contacts of patients, such as roommates and ward mates, can develop asymptomatic colonization, which puts them at risk for invasive infections, and these colonized patients can, in turn, serve as a source of transmission to others. Currently, data on effective decolonization methods for C. auris are lacking. It is important to identify colonized patients and implement appropriate infection control measures to stop transmission.
• Most U.S. C. auris isolates have been resistant to at least one antifungal, most commonly fluconazole, and patients have developed resistance to echinocandin drugs while on treatment. Amphotericin B resistance has also been seen in about 30% of isolates. Echinocandin drugs are the first-line treatment for most invasive Candida infections, making resistance to this class of antifungal drugs particularly concerning. As of September 15, 2017, at least five patients in the United States had echinocandin-resistant isolates. In one patient, resistance to echinocandin drugs developed while being treated with echinocandins. Based on these findings, CDC is concerned that echinocandin-resistant C. auris could become more common.
• Some commonly used healthcare disinfectants are not sufficiently effective against C. auris. C. auris can persist in healthcare environments for several weeks. Testing suggests that certain quaternary ammonium-based disinfectants, commonly used in healthcare settings, do not have sufficient activity against C. auris. At this time, CDC recommends use of an Environmental Protection Agency (EPA)-registered disinfectant effective against Clostridium difficile spores.

To help prevent the spread of C. auris, CDC has developed recommendations for healthcare facilities and local health departments when a case of C. auris is suspected or confirmed. The key to controlling its spread is rapidly identifying infected or colonized patients, and implementing effective infection control measures including hand hygiene, adherence to contact precautions, and performing thorough environmental disinfection.

Based on these recent findings, CDC has developed the following recommendations for healthcare providers and laboratories:

1. Test all Candida isolates obtained from the bloodstream and other normally sterile, invasive body sites (e.g., cerebrospinal fluid) to determine the species. Species identification will not only help with selection of appropriate treatment of invasive candidiasis, but also identify C. auris when present. Please refer to the Recommendation for Identification of C. auris for more information about how to accurately identify C. auris. Note that C. auris is commonly misidentified as Candida haemulonii and other Candida species.
2. Consider testing Candida isolates from non-sterile, non-invasive sites to determine species in certain situations. C. auris is important to identify even from a non-sterile body site (e.g., urine, wounds, sputum) because presence of C. auris in any clinical specimen indicates the possibility of colonization and therefore a risk for transmission and the need for implementation of infection control precautions. Some clinical laboratories do not typically determine the species of isolates from non-sterile, non-invasive body sites since presence of Candida in these sites may represent colonization rather than infection and may not require treatment. However, facilities should consider determining the species of Candida isolates from non-sterile body sites obtained during the course of routine clinical care in the following situations:
   • When clinically indicated in the care of a patient.
   • When a case of C. auris infection or colonization has been detected in a facility or unit, to detect other colonized patients. Species identification of isolates from non-sterile sites can be implemented for a limited time until there is reasonable evidence that there is no further C. auris transmission.
   • When a patient has had an overnight stay in a healthcare facility outside the United States in the previous one year in a country with documented C. auris transmission, especially those countries to which U.S cases have been linked (India, Pakistan, South Africa, and Venezuela). Colonization for longer than a year has been identified among some C. auris patients; therefore hospitals might also consider determining the species for Candida isolated from patients with more remote exposure to healthcare abroad.
3. As part of the investigation of a patient with newly identified C. auris infection or colonization, screen patients/residents in hospitals or nursing homes that were close contacts to detect transmission. CDC and some regional public health laboratories can assist with screening patients to identify colonization; all regional public health laboratories will be able to assist with colonization testing in the next year. Contact your local or state health department or CDC at candidaauris@cdc.gov for assistance. Patients identified as colonized should be managed with appropriate infection control measures.
4. Patients with C. auris infection should be closely monitored for treatment failure, as indicated by persistently positive clinical cultures (i.e., >5 days). CDC websites provide detailed guidance on treatment and on antifungal susceptibility testing for C. auris.
5. Rooms of patients with C. auris should be cleaned and disinfected (daily and terminal) with an EPA-registered disinfectant effective against Clostridium difficile spores. More details are available in CDC’s recommendations.