C. auris: CDC’s Response to a Global Emerging Threat

Posted On: 2017

Story Highlights
  • Candida auris (C. auris) is an emerging multidrug-resistant yeast that can cause invasive infection and death.
  • After learning from international partners that C. auris had spread between patients in their hospitals—which is unusual for Candida—CDC’s response was swift. Rather than waiting for C. auris to be reported in the United States, CDC released a Clinical Alert in June 2016 asking labs and healthcare workers to be on the lookout for C. auris and report any cases to CDC.
  • Following the clinical alert, healthcare facilities quickly reported several C. auriscases, and CDC began investigating with state and local public health partners. The investigation team described the first seven reported cases in CDC’s November 2016 Morbidity and Mortality Weekly Report (MMWR). Cases from June 2016 to May 2017 are described in CDC’s May 18, 2017 MMWR.
  • CDC continues to actively work with partners to better contain and prevent spread of C. auris.
  • CDC has developed C. auris guidance for clinicians and infection control personnel. CDC is also working with state and local health agencies, healthcare facilities, and clinical microbiology laboratories to ensure that laboratories are using proper methods to detect C. auris to help contain its spread.
  • CDC’s Antimicrobial Resistance Solutions Initiative is transforming the nation’s capacity to further detect, contain, and prevent drug resistant threats like C. auris. Key programs include CDC’s AR Laboratory Network (ARLN), the Emerging Infections Program (EIP), and the AR Isolate Bank.
A strain of C. auris cultured in a petri dish at CDC. Photo Credit: Shawn Lockhart, CDC
A strain of C. auris cultured in a petri dish at CDC. Photo Credit: Shawn Lockhart, CDC

Germs, including bacteria and fungi, can develop resistance to the drugs (i.e., antibiotics and antifungals) design to kill them.

Because most Candida do not spread from person to person, healthcare providers usually do not think of Candida as spreading from patient to patient. However, what is different and particularly scary about Candida auris (C. auris) is that it can last on skin and healthcare surfaces, like bedrails and chairs, for a long time—allowing it to spread from person to person in healthcare settings. C. auris often is not killed by commonly used antifungals, making infections difficult to treat and frequently deadly.

Most strains detected so far have been resistant to at least one drug, and more than one-third were resistant to two drug classes. Particularly concerning, some strains have been found to be resistant to all three drug classes used to treat fungal infections. This level of resistance has never been seen in other Candida infections.

An additional challenge is that specialized laboratory methods are needed to accurately identify C. auris. Conventional or outdated lab techniques in healthcare facilities often lead to misidentification and inappropriate treatment of C. auris, making it difficult to control its spread in healthcare settings. CDC and its Antimicrobial Resistance Laboratory Network (AR Lab Network) regional laboratories are filling this detection gap by providing accurate identification methods and susceptibility testing until healthcare facilities can begin to adopt these new methods.

CDC Works to Contain the Global Emerging Threat

After learning of cases in UK healthcare facilities that were spreading from person to person and in the environment, CDC alerted U.S. healthcare facilities in June 2016 to look for this emerging fungus that can cause severe illnesses in patients. The CDC alert notified healthcare facilities and clinical, state, and public health labs of the following:

  • Some samples of C. auris showed high levels of resistance to all three major antifungal drug classes, which limits the options available for treating the patient.
  • Infections have most commonly been healthcare-associated and occurred several weeks into an inpatient stay.
  • Affected patients have developed bloodstream infections, wound infections, and ear infections.
  • Healthcare providers should be aware of the challenges in identifying this organism because it can easily be misidentified as another type of Candida infection

Healthcare providers should be aware of the challenges in identifying this organism because it can easily be misidentified as another type of Candida infection.

Following the proactive clinical alert to U.S. facilities, CDC was notified of 13 U.S. cases of C. auris infection by November 2016 and investigated together with several state and local health departments.  The details of the first seven U.S. cases reported, which occurred in four states between May 2013 and August 2016, are described in CDC’s November 11, 2016 Morbidity and Mortality Weekly Report (MMWR). All patients had serious medical conditions and had been hospitalized an average of 18 days when C. auris was identified. Four of the seven patients died, but it is not clear if the deaths were associated with the C. auris infection or other existing health conditions. Cases from June 2016 to May 2017 are described in CDC’s May 18, 2017 MMWR. As new cases are reported to CDC and confirmed, they are updated on CDC’s C. auris website.

Findings from CDC’s Gold-Standard Methods

Transformative Investments

CDC is making transformative improvements using resources provided by Congress in fiscal year 2016 to further identify and respond to new and known drug resistance threats with activities like:

  • Healthcare-Associated Infection (HAI)/AR Detect & Respond Programs: CDC is enhancing national infrastructure in 50 states, five major cities/territories, and seven regions to ensure rapid identification and containment of resistant pathogens and mechanism threats, like C. auris, across all healthcare settings.
  • AR Laboratory Network: Regional labs in the AR Lab Network will test for and support response to new forms of Candida resistance in the United States.
  • Emerging Infections Program (EIP): CDC is enhancing tracking of Candida to better understand the yeast through EIP, a national network utilized for tracking, preventing, and controlling emerging infectious diseases.
  • AR Isolate Bank: Diagnostic labs can use CDC’s C. auris samples to calibrate, or standardize, their diagnostic tests so they can accurately identify and characterize this emerging threat.

CDC’s gold-standard laboratories have analyzed hundreds of international samples of C. auris and supported several investigations in the U.S. and abroad. Key findings include:

  • C. auris samples are nearly identical within each hospital, suggesting that C. auris spreads in healthcare settings.
  • C. auris can contaminate patient rooms, which can lead to infection of other patients. To prevent the spread of C. auris in hospitals and nursing homes, healthcare workers, patients, and families should follow recommended infection control practices, such as hand hygiene and room cleaning.
  • CDC used advanced laboratory testing called whole-genome sequencing to better understand the DNA fingerprint of each U.S. and international C. auris sample. These fingerprints help determine where connections may exist between cases. In December 2016, CDC and international partners reported a surprising finding: the DNA fingerprints revealed that C. auris strains seemed to have emerged simultaneously in four different places around the world. Strains within each region were almost identical, but the DNA fingerprints between regions were different.
  • In the United States, most C. auris infections are related to strains from South Asia, but others have been linked to strains from South America and East Asia.
  • It is still not clear why four very distinct strains have emerged almost simultaneously across the globe in the past few years. One possible explanation could be that changes in the use of antifungal medications or fungicides in the environment helped C. auris emerge.

CDC believes that we are still in the window of opportunity to stop the spread of C. auris in the United States. To do so will require an aggressive response to cases and a clearer understanding of the most effective ways to prevent transmission.

CDC Recommendations to Prevent & Track C. auris

CDC has developed C. auris interim recommendations for healthcare facilities and laboratories.

  • CDC recommends that healthcare professionals place patients with auris in single rooms on Standard and Contact Precautions to control its spread within a facility.
  • Healthcare facilities should conduct thorough daily and after-discharge cleaning of rooms of patients with C. auris with an EPA-registered disinfectant effective against Clostridium difficile spores.
  • Healthcare facilities and laboratories should report all C. auris cases to CDC and state and local health departments. CDC can assist in identifying this particular type of Candida if needed.

The challenge of emerging drug resistant threats like C. auris highlights the need for an urgent, comprehensive federal, state, local, and international public health response and the importance of CDC’s Antimicrobial Resistance Solutions Initiative. The timely investments in the AR Solutions Initiative allow CDC to rapidly detect, investigate, and respond to emerging threats, like C. auris; make recommendations to prevent resistant infections from occurring and spreading across healthcare settings and the community; and support the development of new diagnostics and drugs to test, treat, and prevent infections, and save lives.

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