Direct Detection of Emergent Fungal Pathogen Candida auris in Clinical Skin Swabs by SYBR Green-Based Quantitative PCR Assay

Abstract

The recent emergence of the multidrug-resistant and pathogenic yeast Candida auris continues to cause public health concern worldwide. C. auris is alarming because it causes health care-associated outbreaks and can establish invasive infections with high mortality rates. Transmission between patients is facilitated by the ability of C. auris to persistently colonize multiple body sites, including the skin, and survive for weeks on surfaces in health care settings. Rapid identification of colonized patients is needed to implement timely infection control measures. Currently, CDC laboratories use an enrichment culture-based approach that can take up to 2 weeks to identify C. auris from composite swabs from the bilateral axillae and groin. A rapid SYBR green quantitative PCR (qPCR) assay that can identify C. auris in a single day was recently described. In this study, we developed the SYBR green qPCR assay further by incorporating a DNA extraction procedure for skin swabs and by including an internal amplification control based on the distinguishable melt curve of a lambda DNA amplicon. The assay was conducted using 103 clinical axilla/groin skin swab samples. Using the enrichment culture-based approach as a gold standard, we determined that the SYBR green C. auris qPCR has a sensitivity of 0.93 and specificity of 0.96. Overall, we found that the SYBR green C. auris qPCR assay can be successfully applied for rapid and accurate detection of C. auris in patient skin swabs, thereby increasing diagnostic options for this emerging pathogen.

A high‐throughput and rapid method for accurate identification of emerging multidrug‐resistant Candida auris

“…The real‐time PCR assay was very sensitive, with a detection limit of 1 C auris CFU/10 μL or 100 CFU/mL (Figure ). This is similar to the limit of detection reported by Leach et al, but is lower than the limit of detection for the SYBR Green method of real‐time PCR reported at 4 C auris CFU/PCR reaction …”

Epidemiologic Shift in Candidemia Driven by Candida auris, South Africa, 2016–20171

“…To address the continued transmission of C. auris in health facilities in South Africa, C. auris has been identified as a priority pathogen for surveillance to monitor emergence of antifungal drug resistance from all infection sites. We have also adapted published laboratory methods for rapid identification of C. auris colonization in the context of outbreak investigations (28). Local studies are also being planned to investigate the efficacy of novel antifungal agents (29).…”

Candida auris: A Review of Recommendations for Detection and Control in Healthcare Settings

“…At the time of writing, clinical evaluations of three culture-independent tests using culture-based gold standards have been published. These include a Taqman quantitative PCR (qPCR), a SYBR green qPCR, and a T2 Magnetic Resonance assay; all performed well with clinical sensitivities and specificities close to or exceeding 90% [19][20][21][22][23]. In the United States, the Taqman-based qPCR is currently the mostly widely used culture-independent test and is employed for C. auris surveillance at CDC and the Wadsworth Center in New York, as well as an increasing number of Antibiotic Resistance Laboratory Network (AR Lab Network) laboratories.…”