SARS患者SARS冠状病毒RNA的动态检出特点及其意义

目的 观察SARS患者各种临床标本的带毒状况，分析SARS冠状病毒(SARS-CoV)在患者体内的动态变化及其临床意义。方法设计针对SARS-CoV区和N区的2套引物，应用巢式RT-PCR对84例SARS患者的血、尿、痰、粪便、咽拭子等494份不同发病时间收集的标本进行病毒定性检测，并将PCR产物直接进行DNA序列分析。结果两套引物均能较好地扩增出部分标本SARS-CoV基因的特异性片段。在所有标本中痰液阳性检出率最高，联合检测多种标本或同时应用两套引物进行PCR扩增可明显提高标本阳性检出率。跟踪观察发现，SARS患者发病第2周时PCR阳性检出率最高，第3～4周次之，但各种标本阳性检出率的动态变化不尽相同。结论应用巢式RT-PCR进行SARS早期诊断和检测是一种可行的方法，针对SARS-CoV基因组不同区域设计多对引物，联合检测多种临床标本可明显提高阳性检出率；研究SARS-CoV的检出变化特点将为SARS的临床治疗提供一定的依据。

Dynamic detection of RNA of SARS-associated coronavirus in blood and excreta of SARS patients

Objective To serially examine virus carrying condition of clinical specimens collected from SARS patients, in order to evaluate the dynamic changes of virus in the bady and its clinical significance. Methods A total of 494 samples, including plasma, urine, feces, sputum and throat swab, obtained from 84 cases of clinically diagnesed SARS patients at different time-points were examined for the study. Nested RT-PCR was employed for the detection of SARS-CoV using 2 pairs of primers targeting P and N region of the viral genome. The amplified viral genomic fragments were confirmed by DNA sequence analysis. Results Specific bands for SARS-CoV were amplified from various specimens of some SARS patients. Highest positive rate was found in sputum compared with the others. However, simultaneous examination of more than two specimens increased detectable rate of the virus. Moreover, dynamic examination revealed that the highest positive rate occurred in the 2nd week after the onset of the disease and next to the highest during the 3rd to 4th week. However, dynamic detectable rates for different specimens were not identical. Conclusion Nested RT-PCR is a practicable method for the detection of SARS-CoV and helpful for the early diagnosis or confirmation of the disease. Dynamic examinations for SARS-CoV by combined employment of the N and P primers and by involving multiple specimens may significantly increase the positive detectable rate, therefore would be helpful in diagnosis and eratuation of therapeutic effect of SARS.