Evaluation of a new T2 Magnetic Resonance assay for rapid detection of emergent fungal pathogen Candida auris on clinical skin swab samples

Candida auris is a multidrug-resistant pathogenic yeast whose recent emergence is of increasing public-health concern. C.auris can colonise multiple body sites, including patients' skin, and survive for weeks in the health care environment, facilitating patient-to-patient transmission and fueling health care-associated outbreaks. Rapid and accurate detection of C.auris colonisation is essential for timely implementation of infection control measures and to prevent transmission. Currently, axilla/groin composite swabs, used to assess colonisation status, are processed using a culture-based method that is sensitive and specific but requires 14days. This delay limits the opportunity to respond and highlights the need for a faster alternative. The culture-independent T2 Magnetic Resonance (T2MR) system is a rapid diagnostic platform shown to detect target pathogens of interest from unprocessed blood samples in <5hours. In this study, a new C.auris-specific T2 assay was evaluated for screening of the skin surveillance samples. Inclusivity and limit of detection of the T2 C. auris assay were assessed with spiked samples in a representative skin flora background. The T2 C.auris assay recognised isolates from each of the 4 known clades of C.auris and consistently detected cells at 5CFU/mL. Finally, 89 clinical axilla/groin swab samples were processed with the T2 C.auris assay. The culture-based diagnostic assay was used as a gold standard to determine performance statistics including sensitivity (0.89) and specificity (0.98). Overall, the T2 C.auris assay performed well as a rapid diagnostic and could help expedite the detection of C.auris in patient skin swabs.