Background Upper respiratory samples used to test for SARS-CoV-2 virus may be infectious and present a hazard during transport and testing. A buffer with the ability to inactivate SARS-CoV-2 at the time of sample collection could simplify and expand testing for COVID-19 to non-conventional settings. Methods We evaluated a guanidium thiocyanate-based buffer, eNAT ™ (Copan) as a possible transport and inactivation medium for downstream Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) testing to detect SARS-CoV-2. Inactivation of SARS-CoV-2 USA-WA1/2020 in eNAT and in diluted saliva was studied at different incubation times. The stability of viral RNA in eNAT was also evaluated for up to 7 days at room temperature (28°C), refrigerated conditions (4°C) and at 35°C. Results SARS-COV-2 virus spiked directly in eNAT could be inactivated at >5.6 log 10 PFU/ml within a minute of incubation. When saliva was diluted 1:1 in eNAT, no cytopathic effect (CPE) on VeroE6 cells was observed, although SARS-CoV-2 RNA could be detected even after 30 min incubation and after two cell culture passages. A 1:2 (saliva:eNAT) dilution abrogated both CPE and detectable viral RNA after as little as 5 min incubation in eNAT. SARS-CoV-2 RNA from virus spiked at 5X the limit of detection remained positive up to 7 days of incubation in all tested conditions. Conclusion eNAT and similar guanidinium thiocyanate-based media may be of value for transport, stabilization, and processing of clinical samples for RT-PCR based SARS-CoV-2 detection.
【초록키워드】 COVID-19, SARS-CoV-2, Saliva, media, SARS-CoV-2 virus, RT-PCR, virus, clinical samples, SARS-CoV-2 detection, stability, Viral, inactivation, Cell culture, limit of detection, temperature, SARS-CoV-2 RNA, Viral RNA, infectious, respiratory, Incubation, inactivated, CPE, Cytopathic effect, Dilution, Chain Reaction, room temperature, Transport, reaction, medium, chain, minute, hazard, processing, VeroE6 cells, positive, sample collection, upper, downstream, buffer, Copan, guanidinium, SARS-CoV-2 USA-WA1/2020, respiratory sample, log, clinical sample, Result, tested, detect, remained, detectable, evaluated, condition, conditions, expand, abrogated, 1:1, passages, VeroE6 cell, 【제목키워드】 diagnostic, medium,