不同灭活温度对新型冠状病毒核酸检测的影响

Effect of the thermal inactivation on SARS-CoV-2 at different temperatures on real-time quantitative PCR detection

目的探讨不同灭活温度处理对新型冠状病毒核酸检测的影响。方法收集该中心2020年1月25至2月25日采集的新型冠状病毒核酸检测阳性标本14份,每份标本分别采取未灭活56℃、35 min和65℃、15 min恒温金属浴灭活处理,比较未灭活标本和灭活标本循环阈值(Ct值),并进行统计学分析。结果未灭活组和56℃、35 min灭活处理组,未灭活组和65℃、15 min灭活处理组,56℃、35 min灭活处理组和65℃、15 min灭活处理组开放读码框1ab(ORF1ab)、核衣壳蛋白(N)基因扩增Ct值差异均无统计学意义(P>0.05)。在Ct值≥34的标本中未灭活组和56℃、35 min灭活处理组,未灭活组和65℃、15 min灭活处理组,56℃、35 min灭活处理组和65℃、15 min灭活处理组ORF1ab、N基因扩增Ct值差异均无统计学意义(P>0.05)。在Ct值<34的标本中未灭活组和56℃、35 min灭活处理组,未灭活组和65℃、15 min灭活处理组,56℃、35 min灭活处理组和65℃、15 min灭活处理组ORF1ab、N基因扩增Ct值差异均无统计学意义(P>0.05)。结论使用56℃、35 min灭活处理和65℃、15 min灭活处理新型冠状病毒标本对核酸检测结果无明显影响,对Ct值较大标本也未发现有明显影响,对于试验条件有限的基层检测机构可以采用上述方式处理标本以保护实验人员安全。

Objective To explore the effect of the thermal inactivation on SARS-CoV-2 at different temperatures.Methods A total of 14 clinical samples from patients whose nucleic acid tests were positive for SARS-CoV-2 from January 25 to February 25,2020 in our medical center were collected.Each sample was treated at 56℃and 65℃for 35 minutes and 15 minutes in a constant temperature metal bath,respectively.The differences of cycle threshold(Ct)between non-inactivated samples and inactivated samples were determined,and the data were statistically analyzed.Results There were no statistically significant differences in the ORF1ab or N amplified Ct value between non-inactivated group and the inactivated at 56℃for 35 minutes group(P>0.05),the non-inactivated group and the inactivated at 65℃for 15 minutes group(P>0.05),as well as the inactivated at 56℃for 35 minutes group and the inactivated at 65℃for 15 minutes group(P>0.05).In samples with a Ct value greater than 34,there were no statistically significant differences in the ORF1ab or N amplified Ct value among non-inactivated group and the inactivated at 56℃for 35 minutes group(P>0.05),the non-inactivated group and the inactivated at 65℃for 15 minutes group(P>0.05),as well as the inactivated at 56℃for 35 minutes group and the inactivated at 65℃for 15 minutes group(P>0.05).In samples with a Ct value less than 34,there were no statistically significant differences in the ORF1ab or N amplified Ct value among non-inactivated group and the inactivated at 56℃for 35 minutes group(P>0.05),the non-inactivated group and the inactivated at 65℃for 15 minutes group(P>0.05),as well as the inactivated at 56℃for 35 minutes group and the inactivated at 65℃for 15 minutes group(P>0.05).Conclusion The thermal inactivation of SARS-CoV-2 at different temperatures for selected treated time(56℃,35 minutes and 65℃,15 minutes)has no significant effect on the nucleic acid detected rusults,including in the samples with a large Ct value.For the basic institutions with limited experimental conditions,clinical samples of SARS-CoV-2 could be processed in the manner described in this study to protect laboratory personnel.