Q fever vaccines / 中国人兽共患病学报

Q fever is a worldwide zoonosis and vaccination is the best measure to against its prevalence.Coxiella burnetii (Cb) is an obligate intracellular pathogen responsible for Q fever.Inactivated phase I Cb (Whole cell vaccine,WCV) can provide 100％ protection against Q fever,but its side effect of vaccination is strong.Phase I Cb is treated with chloroform-methanol or trichloroacetic acid and the chloroform-methanol residual (CMR) or the trichloroacetic acid extract (TCA) is used to substitute for WCV.Both CMR and TCA vaccine retain the protective efficient of WCV and significantly reduce the side effects.However,both CMR and TCA vaccine are required to isolate and purify Cb from chick embryos where Cb grows in a biosafety laboratory with the complex procedures.In recent 10 years,the scientists have investigated from protective antigens to CD4+ and CD8+ T cell epitopes of Cb,expecting that the genes encoding the T cell epitopes express highly and induce an efficient protection against Q fever in bodies.

Development of a quantitative real-time polymerase chain reaction for detecting Bartonella henselae / 中华流行病学杂志

<p><b>OBJECTIVE</b>To develop a quantitative real-time polymerase chain reaction (PCR) for detecting Bartonella henselae.</p><p><b>METHODS</b>According to the 16S-23S rRNA intervening sequences (IVS) specific for B. henselae, one pair of primers and one TaqMan-MGB probe were designed. A quantitative real-time PCR was developed with the primers, the probe, and the IVS, a standard template, in DNA sequence detection system (ABI 7900HT).</p><p><b>RESULTS</b>The standard curve was established with the standard template and the relationship between the value of threshold cycle (Ct) and the DNA copy number was linear (r = 0.997). The sensitivity of this quantitative real-time PCR was about 1000 times higher than that of a common PCR used to detect homologous DNA. By this quantitative real-time PCR, the DNA sample of B. henselae was positively detected but not from other rickettsial or bacterial DNA samples. The variation coefficients of intra- and inter-assay reproducibility were 0.2%-1.9%. Using the real-time quantitative PCR to detect samples from mice that were experimentally infected with B. henselae, the small amount of B. henselae DNA was detected in blood samples on days 2, 3, and 5 and large amount of B. henselae DNA was detected in spleen samples on days 1 and 2 after infection.</p><p><b>CONCLUSION</b>Results from our study suggested that this quantitative real-time PCR was highly specific, sensitive and with good repeatability for detection of B. henselae. It seemed quite useful for rapid detection of tiny DNA of B. henselae in various samples and laboratory diagnosis of bartonellosis caused by B. henselae.</p>

Detection of Rickettsia prowazekii by quantitative real-time PCR / 中华流行病学杂志

<p><b>OBJECTIVE</b>To develop a quantitative real-time polymerase chain reaction (PCR) for detecting Rickettsia prowazekii.</p><p><b>METHODS</b>Primers and TaqMan-MGB probes designed based on ompB gene of R. prowazekii, were used to develop this method.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Study on the development of a real-time quantitative polymerase chain reaction assay to detect Rickettsia / 中华流行病学杂志

<p><b>OBJECTIVE</b>To develop a real-time quantitative polymerase chain reaction(PCR) assay for detecting Rickettsia rickettsii.</p><p><b>METHODS</b>The primers and TaqMan-MGB probe were designed according to the ompB gene of R. rickettsii. A DNA fragment of ompB gene amplified from R. rickettsii by PCR was used as a standard template for the development of the method.</p><p><b>RESULTS</b>5 copies of ompB fragments of R. rickettsii were detected. The genomic DNA of R. rickettsii was detected by the developed quantitative PCR assay. However, the genomic DNA from another rickettsial or bacterial agent was not determined. Through this developed method, the positive results were obtained from the animals and cells, artificially infected with R. rickettsii.</p><p><b>CONCLUSION</b>The real-time quantitative PCR assay seemed to be highly sensitive and specific which might be used to rapidly detect R. rickettsia DNA in various samples and to early diagnose patients infected by R. rickettsii.</p>

Molecular biological on rifampim-depending M.Tuberculosis straims isolated from patients / 中华检验医学杂志

Objective To study the molecular biology of rifampin-depending M. Tuberculosis. Methods The seguence (a 319-bp DNA fragment) of rpoB gene were analyzed by automated DNA sequencing machine. (2) The fingerprints of genomic DNA were obtained by random amplified polymorphic DNA (RAPD) fingerprinting. (3)The protein electrophoresis of bacterium by SDS-polyacrylamide gel (SDS-PAG).(4) The cases of pulmonary tuberculosis by rifampin-depending strains were retrospectively analyzed. Results (1) rpoB gene sequenced: The point mutationrate of rifampin-depending strainswas 96.7%(29/30) and that of rifampin-residtant strains 81.1%(30/37), P