[Detection of severe acute respiratory syndrome probable patients' virus RNA in Hangzhou by using a two loci and a modified nested real-time reverse transcription polymerase chain reaction].
OBJECTIVE
To detect the RNA of severe acute respiratory syndrome virus (SARS-CoV) by using reverse transcription polymerase chain reaction (RT-PCR) targeted for a two loci and a modified nested real-time RT-PCR as to improving the reliability and sensitivity of tests.


METHODS
A nested RT-PCR was used for detecting one fragment of SARS-CoV RNA in oropharyngeal swabs from 3 SARS probable patients, 4 SARS suspect patients and other 27 patients with fever in Hangzhou, and the nested RT-PCR product from one SARS probable patient was sequenced. Meanwhile in these 3 SARS probable patients, other three RT-PCR methods, including a hemi-nested RT-PCR targeted for another fragment of SARS-CoV RNA, a real-time RT-PCR and a modified nested real-time RT-PCR, were employed to detect SARS-CoV RNA.


RESULTS
Two positives were found in the 3 SARS probable patients, and none positive in 4 SARS suspect patients and other 27 patients with fever, using the nested RT-PCR. The sequence of the nested RT-PCR product from one SARS probable patient was identified with the counterpart of SARS-CoV genomes published in public database. The results of the hemi-nested RT-PCR, the real-time RT-PCR and the modified nested real-time RT-PCR in the 3 SARS patients were consistent with the one of the nested RT-PCR. During detecting specimen with low copies of RNA, a weak positive signal was produced after about 35 cycles in the real-time RT-PCR, but a strong positive signal was found only after 10 cycles in the modified nested real-time RT-PCR.


CONCLUSIONS
It might improve the reliability of test by employing RT-PCR targeted for two or more fragments in SARS-CoV genome. The modified nested real-time RT-PCR might have higher sensitivity than the routine real-time RT-PCR.
Ye
Rong
R
Department of Microbiology Test, Hangzhou Center for Disease Control and Prevention, Hangzhou 310006, China.
Pan
Jin-cao
JC
Huang
Zhi-cheng
ZC
Wang
Heng
H
Wang
Hao-qiu
HQ
Wei
Dong-fang
DF
Xu
Ke
K
Wen
Hong-gen
HG
Chen
Kang-kai
KK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D006801:Humans; D008875:Middle Aged; D012367:RNA, Viral / Q000235:genetics* / Q000378:metabolism; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics*; D012680:Sensitivity and Specificity; D045169:Severe Acute Respiratory Syndrome / Q000175:diagnosis* / Q000821:virology; D055815:Young Adult
D012367:RNA, Viral