Thirteen cases of Candida auris (C. auris), a serious and sometimes fatal fungal infection that is emerging globally, have been identified in the United States, according to the Centers for Disease Control and Prevention (CDC). Seven of the cases occurred between May 2013 and August 2016 and are described today in CDC's Morbidity and Mortality Weekly Report (MMWR). The other six cases were identified after the period covered by the report and are still under investigation.
Candida auris is a species of fungus that grows as yeast and is ascomycetous. It is one of the few species of the Candida genus that cause the infection candidiasis in humans. Such infections are often acquired in hospital when human immune systems are weakened. In some patients, the yeast can enter the bloodstream and spread throughout the body, causing serious invasive infections. This yeast often does not respond to commonly used antifungal drugs, making infections difficult to treat. Patients who have been in the intensive care unit for a long time or have a central venous catheter placed in a large vein, and have previously received antibiotics or antifungal medications, appear to be at highest risk of infection.
The report is the first to describe U.S. cases of C. auris infection. C. auris is often resistant to antifungal drugs and tends to occur in hospitalized patients. In June 2016, CDC issued a clinical alert describing the global emergence of C. auris and requesting that laboratories report C. auris cases and send patient samples to state and local health departments and CDC. Since then, CDC has been investigating reports of C. auris with several state and local health departments. The agency expects to continue to investigate possible cases as awareness of the emerging infection increases.
"We need to act now to better understand, contain and stop the spread of this drug-resistant fungus," said CDC Director Tom Frieden, M.D., M.P.H. "This is an emerging threat, and we need to protect vulnerable patients and others."
Among the seven cases detailed in the report, patients with C. auris were reported in four states: New York, Illinois, Maryland and New Jersey. All of the patients had serious underlying medical conditions and had been hospitalized an average of 18 days when C. auris was identified. Four of the patients died; it is unclear whether the deaths were associated with C. auris infection or underlying health conditions.
In two instances, two patients had been treated in the same hospital or long-term-care facility and had nearly identical fungal strains. These findings suggest that C. auris could be spread in healthcare settings.
Six of the seven cases were identified through retrospective review of hospital and reference laboratory records. Identifying C. auris requires specialized laboratory methods because it can easily be misidentified as another type of Candida infection, in which case patients may not receive appropriate treatment. Most of the patient samples in the current report were initially misidentified as another species of Candida.
Most of the C. auris strains from U.S. patients (71 percent) showed some drug resistance, making treatment more difficult. Samples of C. auris strains from other countries have been found to be resistant to all three major classes of antifungal medications. However, none of the U.S. strains in this report were resistant to all three antifungal drug classes. Based on laboratory testing, the U.S. strains were found to be related to strains from South Asia and South America. However, none of the patients travelled to or had any direct links to those regions. Most patients likely acquired the infections locally.
"It appears that C. auris arrived in the United States only in the past few years," said Tom Chiller, M.D., M.P.H., chief of CDC's Mycotic Diseases Branch. "We're working hard with partners to better understand this fungus and how it spreads so we can improve infection control recommendations and help protect people."
CDC recommends that healthcare professionals implement strict Standard and Contact Precautions to control the spread of C. auris. Facilities should conduct thorough daily and after-discharge cleaning of rooms of C. auris patients with an EPA-registered disinfectant active against fungi. Any cases of C. auris should be reported to CDC and state and local health departments. CDC can assist in identifying this particular type of Candida if needed.
In 2013, CDC issued a report describing antibiotic resistance threats in the United States that needed prompt action, including Candida infections. CDC's Antibiotic Resistance Laboratory Network is providing additional lab support in four regional laboratories to test fungal susceptibility of Candida species and identify emerging resistance. CDC is also expanding tracking of this fungus through the Emerging Infections Program. Information gathered through these networks plays a key role in tracking resistance and informing policies and interventions.
The challenge of emerging antibiotic resistant threats like C. auris highlights the need for urgent, coordinated federal, state, local, and international public health response and the importance of CDC's AR Solutions Initiative. The timely investments in the AR Solutions Initiative empower CDC to rapidly detect, investigate, and respond to emerging threats, like C. auris; prevent resistant infections from occurring and spreading across healthcare settings and the community; and innovate, supporting development of new diagnostics and drugs to test, treat, prevent infections, and save lives.
For more information on C. auris, visit https://www.cdc.gov/fungal/diseases/candidiasis/candida-auris.html