Multi-center Evaluation of a PCR-based Digital Microfluidics and Electrochemical Detection System for the Rapid Identification of 15 Fungal Pathogens Directly from Positive Blood Cultures.

Background: Routine identification of fungal pathogens from positive blood cultures by culture-based methods can be time consuming, delaying treatment with appropriate antifungal agents. The GenMark Dx ePlex(R) Investigational Use Only Blood Culture Identification Fungal Pathogen Panel (BCID-FP) rapidly detects 15 fungal targets simultaneously in blood culture samples positive for fungi by Gram stain. We aimed to determine the performance of the BCID-FP in a multi-center clinical study.Materials and Methods: Blood culture samples collected at 10 US sites and tested with BCID-FP at 4 sites were compared to the standard-of-care microbiological and biochemical techniques, PNA-FISH and MALDI-TOF MS. Discrepant results were analyzed by bi-directional PCR/sequencing of residual blood culture samples.Results: A total of 866 clinical samples, 120 retrospectively- and 21 prospectively- collected, along with 725 contrived samples were evaluated. Sensitivity and specificity of the Candida species (C. albicans, C. auris, C. dubliniensis, C. famata, C. glabrata, C. guilliermondii, C, kefyr, C. krusei, C. lusitaniae, C. parapsilosis, C. tropicalis), ranged from 97.1-100% and 99.8-100%, respectively. For the other organism targets, sensitivity and specificity were as follows: 100% each for Cryptococcus neoformans and C. gattii, 98.6% and 100% for Fusarium spp. and 96.2% and 99.9% for Rhodotorula spp. respectively. In 4 of the 141 clinical samples, the BCID-FP Panel correctly identified an additional Candida species, undetected by standard-of-care methods.Conclusion: The BCID-FP Panel offers a faster turnaround time for identification of fungal pathogens in positive blood cultures that may allow for earlier antifungal interventions and, includes C. auris, a highly multi-drug resistant fungus.