Coming to an ICU Near You — Candida auris
Nov. 30, 2017
I first became aware of Candida auris (C. auris) during my 96-year-old mother’s most recent hospitalization in New York for congestive heart failure. The infectious disease epidemiologist called to ask permission to swab my mother’s skin for the yeast, because many cases (with clinical manifestations) had been reported in New York and New Jersey; the hospital was assessing the extent of colonization. After assuring my worried mother that she was not suspected of an active infection, the test was performed. (I have not been informed of the result to date.)
C.auris is an emerging pathogen with multidrug resistance. Difficult to identify using traditional biochemical methods, C. auris is capable of causing invasive fungal infections, particularly among hospitalized patients with significant medical comorbidities.
First isolated from a Japanese patient with external ear drainage in 2009, C. auris has been reported worldwide. C. auris is phylogenetically related to Candida haemulonii and Candida ruelliae, but it does not display pseudohyphae. Only some C. auris strains produce the virulence factors phospholipase and proteinase, which may account for variability in pathogenicity. C. auris is capable of forming biofilms and adhering to catheter material, although not to the same degree as Candida albicans.
Traditional biochemical methods of identification commonly misdiagnose C. auris as another yeast. The CDC recommends further testing for C. auris whenever C. haemulonii is identified. Accurate identification can be performed with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) devices using their “research use only” databases. Molecular sequencing of the D1–D2 domain of the 28s rDNA can also identify C. auris. For laboratories without the capability to perform these tests, a low-cost alternative that can accurately distinguish C. auris from C. haemulonii utilizes CHROMagar medium supplemented with Pal’s medium. (1)
Whole-genome sequencing of C. auris isolates has revealed 4 distinct clades that cluster geographically (South Asia, East Asia, South Africa, and South America) with a high degree of relatedness within clades, suggesting independent emergence with transmission within a geographic area rather than a single emergence and spread. (2)
Schelenz et al reported an ongoing outbreak of 50 C. auris cases between April 2015 and July 2016 within a single Hospital Trust in London. A total of 44 % (n = 22/50) patients developed possible or proven C. auris infection with a candidemia rate of 18 % (n = 9/50). Environmental sampling showed persistent presence of the yeast around bed space areas. Implementation of strict infection and prevention control measures included isolation of cases and their contacts, wearing of personal protective clothing by health care workers, screening of patients on affected wards, skin decontamination with chlorhexidine, environmental cleaning with chorine based reagents and hydrogen peroxide vapor. The authors concluded that this outbreak with genotypically closely related C. auris highlighted the importance of appropriate species identification and rapid detection of cases in order to contain hospital acquired transmission. (3)
Therapeutically, C. auris is resistant to fluconazole. The CDC recommends that all C. auris isolates undergo susceptibility testing. Echinocandins (anidulafungin, caspofungin, and micafungin) are considered most effective. Amphotericin B is likely less reliable as empiric therapy. (1) Cases of development of resistance to echinocandins to C. auris while on therapy have occurred. (4)
As of September 2017, a total of 127 confirmed and 27 probable cases from 10 states have been reported to the CDC. New York and New Jersey have identified the majority of confirmed cases, reporting 86 and 26, respectively. (5)
The presence of a single case in a healthcare facility should prompt an aggressive response and investigation because C. auris can cause healthcare-associated outbreaks. Patients can remain colonized on their skin and other body sites indefinitely after resolution of invasive infections, allowing C. auris to be shed into the healthcare environment, where it persists on surfaces and can be transmitted to other patients. Containment efforts should focus on identifying patients who are infected or colonized with C. auris and implementing infection control interventions, including hand hygiene, contact precautions, and thorough environmental cleaning and disinfection. (2)
As the number of cases of candidemia due to C. auris proliferates (6), unquestionably dermatologists will be identifying cutaneous lesions due to septic emboli for patients at risk.
As with all emerging infections, it is essential to keep current with the latest information — this is available on the CDC website: www.cdc.gov/fungal/diseases/candidiasis/candida-auris.html
1. Sears D, Schwartz BS. Candida auris: An emerging multidrug-resistant pathogen. Int J Infect Dis 2017; 63: 95-8.
2. Tsay S, et al. Approach to the investigation and management of patients with Candida auris, an emerging multidrug-resistant yeast. Clin Infect Dis 2017; Aug 17 [Epub ahead of print].
3. Schelenz S, et al. First hospital outbreak of the globally emerging Candida auris in a European hospital. Antimicrob Resist Infect Control 2016; 5: 35.
4. Brunk D. Superbug ‘thrives on skin’. Dermatology News 2017; 48; 1; 6.
Spivak ES, Hanson KE. Candida auris: An emerging pathogen. J Clin Microbiol 2017; Nov 22 [Epub ahead of print]
5. Al-Siyabi T, et al. First report of Candida auris in Oman: Clinical and microbiological description of five candidemia cases. J Infect 2017; 75: 373-6.
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