[Detection of Rickettsia prowazekii by quantitative real-time PCR].
OBJECTIVE
To develop a quantitative real-time polymerase chain reaction (PCR) for detecting Rickettsia prowazekii.


METHODS
Primers and TaqMan-MGB probes designed based on ompB gene of R. prowazekii, were used to develop this method.


RESULTS
For the quantitative real-time PCR, the relationship between the values of threshold cycle (Ct) and the DNA copy number was linear (r = 0.999) and the sensitivity was about 100 times higher than that of the nested PCR for detecting the same DNA sample. The results of the genomic DNA samples of other rickettsial and bacterial agents detected by real-time PCR were all negative. DNAs extracted from blood samples of guinea pig infected with R. prowazekii were examined by real-time PCR and the positive results were obtained from some of these samples. However, the results of some samples in nested PCR assay were all negative.


CONCLUSIONS
These results suggested that the real-time PCR was highly specific and sensitive for detection of R. prowazekii that was useful for the detection of tiny DNA of R. prowazekii in blood samples from patients suspected of having epidemic typhus.
Yang
Xiao
X
Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences , Beijing 100071, China.
Chen
Mei-ling
ML
Wen
Bo-hai
BH
Niu
Dong-sheng
DS
Zhu
Li-na
LN
Li
Qing-feng
QF
Sun
Chang-jian
CJ
D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012283:Rickettsia prowazekii / Q000235:genetics* / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D014438:Typhus, Epidemic Louse-Borne / Q000175:diagnosis
D017931:DNA Primers; D004269:DNA, Bacterial