Analytical and clinical evaluation of the PathoNostics AsperGenius Assay for detection of invasive aspergillosis and resistance to azole antifungal drugs directly from plasma samples

White, P. Lewis, Posso, Raquel B., Barnes, Rosemary A. and Warnock, David W. 2017. Analytical and clinical evaluation of the PathoNostics AsperGenius Assay for detection of invasive aspergillosis and resistance to azole antifungal drugs directly from plasma samples. Journal of Clinical Microbiology 55 (8) , pp. 2356-2366. 10.1128/JCM.00411-17

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Abstract

With the proposal to include Aspergillus PCR in the revised European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) definitions for fungal disease, commercially manufactured assays may be required to provide standardization and accessibility. The PathoNostics AsperGenius assay represents one such test that has the ability to detect a range of Aspergillus species as well as azole resistance in Aspergillus fumigatus. Its performance has been validated on bronchoalveolar lavage (BAL) fluid and serum specimens, but recent evidence suggests that testing of plasma may have enhanced sensitivity over that with serum. We decided to evaluate the analytical and clinical performances of the PathoNostics AsperGenius assay for testing of plasma. For the analytical evaluations, plasma was spiked with various concentrations of Aspergillus genomic DNA before extraction following international recommendations, using two automated platforms. For the clinical study, 211 samples from 10 proven/probable invasive aspergillosis (IA) and 2 possible IA cases and 27 controls were tested. The limits of detection for testing of DNA extracted using the bioMérieux EasyMag and Qiagen EZ1 extractors were 5 and 10 genomes/0.5-ml sample, respectively. In the clinical study, true positivity was significantly greater than false positivity (P < 0.0001). The sensitivity and specificity obtained using a single positive result as significant were 80% and 77.8%, respectively. If multiple samples were required to be positive, specificity was increased to 100%, albeit sensitivity was reduced to 50%. The AsperGenius assay provided good clinical performance, but the predicted improvement of testing with plasma was not seen, possibly as a result of target degradation attributed to sample storage. Prospective testing is required to determine the clinical utility of this assay, particularly for the diagnosis of azole-resistant disease.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Medicine
Publisher:	American Society for Microbiology
ISSN:	0095-1137
Date of First Compliant Deposit:	29 November 2017
Date of Acceptance:	9 May 2017
Last Modified:	14 Nov 2024 16:30
URI:	https://orca.cardiff.ac.uk/id/eprint/107081

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