On May 19, 2017, the CDC published a report that found the total number of U.S. clinical cases of the highly virulent, multidrug-resistant, yeast pathogen Candida auris (C. auris) rose from 7, as of August 2016, to 77, as of May 12, 2017.
As of a November 4, 2016, announcement by the CDC, 13 cases of C. auris, a serious and sometimes fatal fungal infection that is emerging globally, had been identified in the United States. Seven of the cases occurred in the three years and three months between May 2013 and August 2016. The other six cases were identified in the four months between August 2016 and November 4, 2016. Another 64 cases were reported in the seven months between November 4, 2016, and May 19, 2017.
The yeast pathogen C. auris was first detected in 2009 from an ear canal infection in Japan. This species of Candida initially attracted attention because of its reduced susceptibility to azoles, a class of oral antifungal drugs for the treatment of systemic fungal infections, and amphotericin B, an antifungal medication used for serious fungal infections, combined with the lack of reliable culture-based methods for its identification. In addition to its multidrug-resistance, C. auris is also noteworthy for its virulence, the severity of the disease it causes.
More recently, C. auris has been associated globally with life-threatening invasive nosocomial diseases, such as bloodstream and wound infections. C. auris has caused hospital outbreaks across Asia and South America. In a UK intensive care unit, candidemia, the fourth most common cause of nosocomial bloodstream infections, developed in 20% of patients colonized with C. auris.
As of May 12, 2017, a total of 77 U.S. clinical cases of C. auris had been reported to CDC from seven states: New York (53 cases), New Jersey (16), Illinois (four), Indiana (one), Maryland (one), Massachusetts (one), and Oklahoma (one). All of these cases were identified through cultures taken as part of routine patient care (clinical cases). Screening of close contacts of these patients, primarily of patients on the same ward in healthcare facilities, identified an additional 45 patients with C. auris isolated from one or more body sites (screening cases), resulting in a total of 122 patients from whom C. auris has been isolated.
Most (69, 90%) clinical cases were identified in the New York City metropolitan area (53 in New York and 16 in New Jersey). Nearly all patients had multiple underlying medical conditions and extensive healthcare facility exposure. Epidemiologic links have been found between most cases. In Illinois, three cases were associated with the same long-term care facility. In New York and New Jersey, cases were identified in multiple acute care hospitals, but further investigation found most had overlapping stays at interconnected long-term care facilities and acute care hospitals within a limited geographic area. The case in Massachusetts was linked to the Illinois cases. The cases in Indiana and Oklahoma occurred in patients who had recently received healthcare in other countries.
Among the 77 clinical cases, the median patient age was 70 years (range = 21–96 years), and 55% were male. C. auris was cultured from the following sites: blood (45 isolates), urine (11), respiratory tract (eight), bile fluid (four), wound (four), central venous catheter tip (two), bone (one), ear (one), and a jejunal biopsy (one). Antifungal susceptibility testing at the CDC of the first 35 clinical isolates revealed that 30 (86%) isolates were resistant to fluconazole (minimum inhibitory concentration [MIC] >32); 15 (43%) were resistant to amphotericin B (MIC ≥2); and one (3%) was resistant to echinocandins (MIC >4), a class of antifungal drugs that target the fungal cell wall.
Testing for C. auris colonization, using a composite swab of the groin and axilla, was conducted for 390 close contacts of the 77 patients in three states, primarily patients on the same ward in healthcare facilities because of the risk for environmental contamination and transmission from healthcare personnel. The two body sites tested were selected based on results of previous investigations. Forty-five (12%) colonized persons were identified (24 in New Jersey, 17 in New York, and four in Illinois). Contact Precautions were recommended for colonized patients in healthcare facilities. Nasal swabs also were collected from 184 (47%) contacts; two swabs (1%) were positive, both from patients with positive groin/axilla swabs. Environmental testing of patients’ rooms identified C. auris from mattresses, beds, windowsills, chairs, infusion pumps, and countertops, indicating C. auris environmental contamination. C. auris was not isolated from rooms after thorough cleaning with a sodium hypochlorite–based disinfectant.
All C. auris isolates were forwarded to the CDC for whole-genome sequencing and comparison with previously sequenced international isolates, which clustered into four distinct clades, groups of organisms believed to have evolved from a common ancestor. Isolates from within each state were highly related. New York isolates, with the exception of one clinical and one screening case, were highly related to one another and grouped in the same clade as isolates from South Asia. Isolates in New Jersey also were similar to those from South Asia but were distinct from those in New York. Illinois isolates were nearly identical to one another and grouped with isolates from South America. These data suggest multiple introductions of C. auris into the United States followed by local transmission.
Ongoing investigation of U.S. C. auris cases provides epidemiologic and laboratory data suggesting that this fungus can spread within healthcare facilities and that interventions are needed to prevent transmission during this early stage of C. auris emergence. As of May 2017, recognized U.S. C. auris cases were concentrated in healthcare facilities in three separate geographic areas, and most cases were in chronically ill patients with long stays at high-acuity skilled nursing facilities (e.g., facilities providing mechanical ventilation). Apart from one case identified in 2013, clinical laboratories serving healthcare facilities with C. auris cases have not identified suspected C. auris isolates from before 2015 from retrospective microbiology record reviews, suggesting recent C. auris emergence in those locations. However, the disease might exist elsewhere, because some laboratories do not fully characterize Candida species or are otherwise unable to detect C. auris.
The CDC has worked with state and local partners to develop and share infection control recommendations to help curb the spread of C. auris. Current recommendations for C. auris–colonized or infected patients include (1) use of Standard Precautions and Contact Precautions, (2) housing the patient in a private room, (3) daily and terminal cleaning of a patient’s room with a disinfectant active against Clostridium difficile spores (an update from previous disinfectant recommendations), and (4) notification of receiving healthcare facilities when a patient with C. auris colonization or infection is transferred. Accurate identification of C. auris and adherence to infection control practices, coupled with ongoing public health surveillance and investigations, are needed to halt the spread of C. auris in the United States.
See the CDC Report
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