High-Throughput, automated assay for detection of colonization by Candida auris

Abstract

Candida auris is an emerging multidrug-resistant fungal pathogen associated with healthcare-associated outbreaks, persistent colonization, and invasive infections. Increasing demand for surveillance has created a need for high-throughput methods capable of supporting large-scale screening programs. We developed and validated an automated laboratory-developed real-time PCR assay for detection of C. auris colonization on the Hologic Panther Fusion(R) open-access platform and compared its performance with the existing BD MAX assay. Analytical performance was evaluated by assessing limit of detection, accuracy, precision, specificity, inclusivity, reproducibility, and reagent and specimen stability. The Panther Fusion(R) assay demonstrated a limit of detection of approximately 18 CFU/reaction and showed 97% overall agreement with the BD MAX assay. Positive and negative percent agreement were 94% and 100%, respectively, with excellent agreement between methods ({kappa} = 0.94). No cross-reactivity was observed with non-C. auris organisms, all five major C. auris clades were detected, and assay performance remained stable across operators, reagent and specimen storage conditions. Following implementation, 26,838 clinical specimens were tested on the Panther Fusion(R) platform. Retrospective analysis demonstrated lower equivocal (0.28%) and indeterminate (0.09%) rates than those observed on the ABI and BD MAX platforms. Among PCR-positive specimens that underwent culture, the Panther Fusion(R) assay demonstrated 87.24% culture agreement. Because retrospective data were collected during different testing periods and patient populations, comparisons between platforms were not used to assess relative assay sensitivity or specificity. Implementation of the Panther Fusion(R) assay increased surveillance testing capacity from approximately 88 to 500 specimens per shift while maintaining robust analytical performance.