Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.
Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
J Clin Microbiol. 2020 Jul 23;58(8). doi: 10.1128/JCM.01068-20.
Real-time reverse transcription-PCR (RT-PCR) is currently the most sensitive method to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19). However, the correlation between detectable viral RNA and culturable virus in clinical specimens remains unclear. Here, we performed virus culture for 60 specimens that were confirmed to be positive for SARS-CoV-2 RNA by real-time RT-PCR. The virus could be successfully isolated from 12 throat and nine nasopharyngeal swabs and two sputum specimens. The lowest copy number required for virus isolation was determined to be 5.4, 6.0, and 5.7 log genome copies/ml sample for detecting the , , and genes, respectively. We further examined the correlation of genome copy number and virus isolation in different regions of the viral genome, demonstrating that culturable specimens are characterized by high copy numbers with a linear correlation observed between copy numbers of amplicons targeting structural and nonstructural regions. Overall, these results indicate that in addition to the copy number, the integrity of the viral genome should be considered when evaluating the infectivity of clinical SARS-CoV-2 specimens.
实时逆转录聚合酶链反应（RT-PCR）是目前检测导致 2019 年冠状病毒病（COVID-19）的严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）最敏感的方法。然而，临床标本中可检测到的病毒 RNA 与可培养病毒之间的相关性尚不清楚。在这里，我们对通过实时 RT-PCR 确认为 SARS-CoV-2 RNA 阳性的 60 个标本进行了病毒培养。从 12 份咽拭子和 9 份鼻咽拭子以及 2 份痰标本中成功分离出病毒。分离病毒所需的最低拷贝数分别确定为检测、和基因的 5.4、6.0 和 5.7 log 基因组拷贝/ml 样本。我们进一步研究了病毒基因组不同区域的基因组拷贝数与病毒分离之间的相关性，表明可培养标本的特点是高拷贝数，靶向结构和非结构区域的扩增子的拷贝数之间存在线性相关性。总的来说，这些结果表明，在评估临床 SARS-CoV-2 标本的感染性时，除了拷贝数外，还应考虑病毒基因组的完整性。
