Application of the ViroKey® SQ FLEX assay for detection of cytomegalovirus antiviral resistance

Abstract

Background: Cytomegalovirus (CMV) is a viral infection which establishes lifelong latency, often reactivating and causing disease in immunosuppressed individuals, including haematopoietic stem cell transplant (HSCT) recipients. Treatment can be problematic due to antiviral resistance which substantially increases the risk of patient mortality. Diagnostic testing capabilities for CMV antiviral resistance in Australia and elsewhere have traditionally relied on gene-specific Sanger sequencing approaches, however, are now being superseded by next generation sequencing protocols.; Objective: Provide a snapshot of local mutations and explore the feasibility of the ViroKey ࣨ ® SQ FLEX Genotyping Assay (Vela Diagnostics Pty Ltd) by examining sequencing success.; Method: Performed sequencing on adult (n = 38) and paediatric (n = 81) plasma samples, over a large range of viral loads (above and below the assay recommended threshold of ≥1,000 International Units (IU)/mL; noting most of our paediatric samples have loads <1,000 IU/mL).; Results: Eleven test runs (including three repeat runs; 14 to 15 samples per run) were conducted, and four runs were deemed valid. The overall individual sample success rate for the four evaluable test runs was 71.2% (42/59 samples); 80.4% (37/46) samples ≥1,000 IU/mL were valid. Ten clinically important antiviral resistance mutations were detected, the most common being A594V in the UL97 gene, found in 6 (5%) samples.; Conclusions: A range of technical issues were experienced, however with improvement this platform could be a useful addition to routine pathology workflows, providing timely antiviral resistance results for patients undergoing HSCT.; Competing Interests: Declaration of Competing Interest MD Solutions Australasia Pty Ltd provided loan instruments and technical support. Reagents and consumables were purchased by the Children's Hospital Foundation grant (project ID RPC00095). MD solutions Australasia Pty Ltd and Vela Diagnostics played no role in the design, analysis and reporting within this study. The authors declare no conflict of interest. (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)