Büyükzengin Kazım Batıhan, Akçalı Alper, Alkan Sevil, Akdur Gökhan
Osmaniye State Hospital, Medical Microbiology Laboratory, Osmaniye, Türkiye.
Çanakkale Onsekiz Mart University Faculty of Medicine, Department of Medical Microbiology, Çanakkale, Türkiye.
Mikrobiyol Bul. 2024 Jul;58(3):309-320. doi: 10.5578/mb.20240037.
Polymerase chain reaction (PCR) and antigen test (AgT) are frequently used in the diagnosis of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Routine PCR tests that detect the virus genome cannot determine whether the virus is infectious or not. However, detection of subgenomic RNA (sgRNA) produced during the replication period may indicate active viral infection. Active virus detection can offer various health and economic benefits from isolation time to treatment. Antigen tests are also considered as indicators of infectiousness since they can detect viruses above a certain load amount. The aim of this study was to use two different subgenomic RNAs and antigen test instead of genomic RNA to examine the relationship with each other and the clinic in terms of infectiousness. Evaluating the antigen test together with subgenomic RNA as an indicator of infectiousness may show the importance of this test. SARS-CoV-2 PCR positive 109 naso/oropharyngeal swab samples stored at -80 °C were included in the study. In order to confirm the PCR positivity of these samples, E gene PCR was performed and AgT, and E and N sgRNA quantitative real-time reverse transcription-PCR (RT-qPCR) detection was performed. Of the 109 SARSCoV-2 PCR positive samples, 83 (76.14%) had antigen test positivity, 88 (80.73%) had E gene sgRNA, 96 (88.07%) had N gene sgRNA and 97 (89%) had at least one sgRNA positivity.The antigen test was found positive in 77.3% of the samples in which at least one sgRNA was detected and in 66.7% of the negative samples and this difference was not statistically significant (p= 0.475). The difference between E sgRNA and AgT positivity was significant (p= 0.023). N sgRNA was positive in 98.9% of E sgRNA positive samples and 42.9% of the negative samples and this difference was statistically significant (p= 0.0001). The AgT positivity rate was found to be 98.15% (53/54) for cycle threshold (Ct) value ≤ 25, 57.14% (12/21) for Ct 25-30, and 52.94% (18/34) for Ct ≥ 30. The difference in antigen test positivity between E gRNA Ct value ≤ 25 and > 25, ≤ 29 and > 29, < 30 and ≥ 30 was statistically significant (p= 0.0001). Antigen test positivity appears to be associated with viral load and infectivity, as expected. In our study, it has been shown that sgRNAs and AgT which are indicators of infectiousness can be detected at least 10 days after the symptom period. Using these two tests together could detect infective individuals with higher accuracy and shorten the duration of hospital stay and isolation.
聚合酶链反应（PCR）和抗原检测（AgT）常用于严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的诊断。检测病毒基因组的常规PCR检测无法确定病毒是否具有传染性。然而，检测复制期产生的亚基因组RNA（sgRNA）可能表明病毒处于活跃感染状态。从隔离时间到治疗，检测活跃病毒可带来各种健康和经济效益。抗原检测也被视为传染性的指标，因为它们可以检测出高于一定载量的病毒。本研究的目的是使用两种不同的亚基因组RNA和抗原检测，而不是基因组RNA，来研究它们在传染性方面的相互关系以及与临床情况的关系。将抗原检测与亚基因组RNA一起作为传染性指标进行评估，可能会显示出该检测的重要性。本研究纳入了109份储存在-80°C的SARS-CoV-2 PCR阳性鼻咽拭子样本。为了确认这些样本的PCR阳性结果，进行了E基因PCR，并进行了AgT以及E和N sgRNA定量实时逆转录PCR（RT-qPCR）检测。在109份SARS-CoV-2 PCR阳性样本中，83份（76.14%）抗原检测呈阳性，88份（80.73%）有E基因sgRNA，96份（88.07%）有N基因sgRNA，97份（89%）至少有一个sgRNA呈阳性。在至少检测到一种sgRNA的样本中，77.3%的样本抗原检测呈阳性，在阴性样本中这一比例为66.7%，差异无统计学意义（p=0.475）。E sgRNA与AgT阳性之间的差异具有统计学意义（p=0.023）。在E sgRNA阳性样本中，N sgRNA阳性率为98.9%，在阴性样本中为42.9%，差异具有统计学意义（p=0.0001）。对于循环阈值（Ct）值≤25的样本，AgT阳性率为98.15%（53/54），Ct为25-30的样本为57.14%（12/21），Ct≥30的样本为52.94%（18/34）。E gRNA Ct值≤25与>25、≤29与>29、<30与≥30之间抗原检测阳性的差异具有统计学意义（p=0.0001）。正如预期的那样，抗原检测阳性似乎与病毒载量和传染性相关。在我们的研究中，已表明作为传染性指标的sgRNAs和AgT至少在症状期后10天仍可检测到。同时使用这两种检测方法可以更准确地检测出感染个体，并缩短住院和隔离时间。
