[Detection of Rickettsia prowazekii by quantitative real-time PCR]

To develop a quantitative real-time polymerase chain reaction (PCR) for detecting Rickettsia prowazekii.

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

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.

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.