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

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.