[Rapid identification of Beijing measles vaccine virus and wild virus by multiplex real-time fluorescent PCR].
OBJECTIVE
To identify wild measles virus and vaccine virus by detection nucleic acid of clinical samples from measles patients with immunization history circulating in Beijing through multiplex real-time fluorescent PCR technology.


METHODS
From July 2011 to February 2012, 10 throat swabs and 15 urine specimens were collected from 16 suspected measles patients who were 8 - 9 months old infants with immunization history in Beijing. The specificity of multiplex real-time fluorescent PCR was firstly tested by measles vaccine virus, wild virus and other respiratory virus. Then the vaccine virus and wild virus were titrated and diluted to test the sensitivity of the PCR method. The result was then compared with it analyzed by PCR-RFLP method. Meanwhile, the clinical sample of the measles patients were tested and confirmed by sequencing method.


RESULTS
The primer-probe sets of Fam, Joe and Cy5 showed great specificity of measles virus, and could distinguish the measles vaccine virus and wild virus well. The sensitivity of this method to detect measles vaccine virus reached 0.1 CCID(50)/0.1 ml; and the sensitivity to wild virus reached 0.006 CCID(50)/0.1 ml; which were both higher than the sensitivity of PCR-RFLP method. Out of the 16 measles patients with vaccination history, 3 were negative and the other 13 all belonged to measles virus genotype A, and were confirmed to be vaccine virus by sequencing method.


CONCLUSIONS
Multiplex real-time PCR method is accurate, rapid and sensitive to identify measles vaccine virus and wild virus. The method could greatly help us to find measles patients and to identify the vaccine-related cases.
Institute for Immunization and Prevention of Beijing Center for Disease Prevention and Control, Beijing 100013, China.
Meng
M
Chen
Fang
F
Huang
Wei-xin
WX
Chen
Mei
M
Dong
Tie-gang
TG
Zhang
Jiang
J
Wu
D002681:China / Q000453:epidemiology; D017931:DNA Primers; D006801:Humans; D007223:Infant; D008458:Measles Vaccine; D008459:Measles virus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D060885:Multiplex Polymerase Chain Reaction; D012367:RNA, Viral / Q000235:genetics; D012680:Sensitivity and Specificity
D017931:DNA Primers; D008458:Measles Vaccine; D012367:RNA, Viral