Sequencing Unit, National Institute of Genomic Medicine, Mexico City, Mexico.
Computational and Integrative Genomics, National Institute of Genomic Medicine, Mexico City, Mexico.
PLoS One. 2021 Aug 18;16(8):e0255807. doi: 10.1371/journal.pone.0255807. eCollection 2021.
The use of saliva for the diagnosis of SARS-CoV-2 has shown to be a good alternative to nasopharyngeal swabs (NPS), since it permits self-collection, avoids the exposure of healthy persons to infected patients, reduces waiting times, eliminates the need of personal protective equipment and is non-invasive. Yet current saliva testing is still expensive due to the need of specialized tubes containing buffers to stabilize the RNA of SARS-CoV-2 and inactivate the virus. These tubes are expensive and not always accessible in sufficient quantities. We now developed an alternative saliva testing method, using TRIzol for extraction, viral inactivation, and storage of SARS-CoV-2 RNA, combined with RT-qPCR, which was comparable in its performance to NPS. Paired saliva samples and NPS were taken from 15 asymptomatic healthcare workers and one patient with SARS-CoV-2. Further 13 patients with SARS-CoV-2 were only saliva-tested. All the tests were performed according to CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel. Saliva (4 mL) was taken in sterile 50 mL tubes, 1.5 mL TRIzol were added and mixed. Our results show that 5 μL of saliva RNA extracted with TRIzol allow for an adequate detection of the virus in patients positive for SARS-CoV-2 and was equally sensitive to NPS in TRIzol. We conclude that saliva testing using TRIzol is a recommendable method for diagnosis of SARS-CoV-2 since it has several advantages over currently used saliva tests: it can be done with normal sterile tubes, does not need cold-chain handling, is stable at room temperature, is non-invasive and less costly, making it more accessible for low-income countries. Cheaper saliva testing using TRIzol is especially relevant for low-income countries to optimize diagnosis and help define quarantine durations for families, healthcare workers, schools, and other public workplaces, thus decreasing infections and mortality caused by SARS-CoV-2.
唾液用于 SARS-CoV-2 的诊断已被证明是鼻咽拭子（NPS）的良好替代方法，因为它允许自我采集，避免健康人暴露于感染患者，减少等待时间，消除对个人防护设备的需求，并且是非侵入性的。然而，由于需要专门的含缓冲液的管来稳定 SARS-CoV-2 的 RNA 并使病毒失活，因此当前的唾液检测仍然很昂贵。这些管昂贵且并不总是以足够的数量获得。我们现在开发了一种替代的唾液检测方法，使用 TRIzol 进行提取、病毒灭活和 SARS-CoV-2 RNA 的储存，并结合 RT-qPCR，其性能与 NPS 相当。从 15 名无症状医护人员和 1 名 SARS-CoV-2 患者中采集了配对的唾液样本和 NPS。进一步对 13 名仅进行唾液检测的 SARS-CoV-2 患者进行了检测。所有检测均根据 CDC 2019-新型冠状病毒（2019-nCoV）实时 RT-PCR 诊断试剂盒进行。在无菌 50 mL 管中采集 4 mL 唾液，加入 1.5 mL TRIzol 并混合。我们的结果表明，TRIzol 提取的 5 μL 唾液 RNA 足以检测 SARS-CoV-2 阳性患者中的病毒，并且与 TRIzol 中的 NPS 一样敏感。我们得出结论，使用 TRIzol 的唾液检测是 SARS-CoV-2 诊断的一种推荐方法，因为它与目前使用的唾液检测相比具有几个优势：它可以用普通的无菌管进行，不需要冷链处理，在室温下稳定，非侵入性且成本较低，使中低收入国家更容易获得。使用 TRIzol 的更廉价的唾液检测对于中低收入国家尤为重要，可优化诊断并有助于确定家庭、医护人员、学校和其他公共场所的隔离期限，从而降低由 SARS-CoV-2 引起的感染和死亡率。
