猪源粪肠球菌和屎肠球菌多重PCR快速鉴定方法的建立

粪肠球菌和屎肠球菌是引起猪感染发病的优势肠球菌种,以肠球菌的16 S rRNA基因设计属特异性引物,利用SodA基因多态性设计种特异性引物,同时优化反应条件,建立了能同时测定猪源粪肠球菌和屎肠球菌多重PCR方法。通过对来源于猪的临床菌株、粪便菌株和鲜猪肉菌株进行测定,均能成功扩增出属特异性片段和种特异性片段。经过与快速生化鉴定试剂盒(Vitek-32)和16 S rRNA测序方法比较,多重PCR与16 S rRNA测序方法对猪的临床菌株、粪便菌株和鲜猪肉菌株的鉴定符合率100%;与Vitek-32鉴定符合率为62.3%,其中,与分离于感染猪的临床菌株符合率仅有46.7%,特别是感染猪的屎肠球菌,符合率仅为22.3%。     

16S-23S rRNA基因间隔序列PCR及RFLP对奇异变形杆菌分离株的鉴别与系统发育分析

根据临床常见致病菌16S-23S rRNA基因间隔序列(ISR)两端的16S及23S rRNA保守序列设计PCR扩增的通用引物,对9株奇异变形杆菌和6株相近菌株应用通用引物PCR扩增16S-23S rRNA ISR序列.通过PCR长度多态性比较、RFLP分析以及部分序列测序比较,分析鉴别奇异变形杆菌.结果显示,PCR长度多态性可以将奇异变形杆菌同其余菌种进行区分;RFLP分析可以将所有试验菌种进行区分;部分序列测序可以对奇异变形杆菌进行分型.由此表明,16S 23S rRNA ISR序列PCR及RFLP分析可以简单、快速、准确的鉴定奇异变形杆菌.     

16S rRNA基因测序法鉴定猪多杀性巴氏杆菌的研究

对66株猪多杀性巴氏杆菌的鉴定结果表明,PCR是一种快速、特异、灵敏的病原检测方法。应用能够扩增大多数原核生物16S rRNA基因的通用引物,对猪多杀性巴氏杆菌疫苗株(EO630)和野外分离株的16S基因rRNA进行PCR扩增,以期为分子水平上准确地鉴别猪巴氏杆菌提供依据。     

猪支原体不同靶基因PCR检测方法的比较

为筛选出检测猪支原体更为特异、敏感的PCR检测方法,本试验分别以16S rRNA、50S rRNA和膜蛋白OxaA为靶基因进行PCR检测,并从其敏感性、特异性和临床样本检出率等方面进行了比较。结果显示,以膜蛋白OxaA和16S rRNA为靶基因的PCR方法敏感性最高,最小检测DNA量为1.86 fg/μL,而以50S rRNA为靶基因的PCR方法最小检测DNA量为18.6 fg/μL;3种靶基因引物均扩增不出大肠杆菌、猪链球菌、猪肺炎支原体、牛附红细胞体等基因片段,具有较好的特异性;通过对临床60份血液样本的检测结果表明,以膜蛋白OxaA基因设计的引物检出率最高,为25%(15/60),明显高于16S rRNA基因的21.6%(13/60)和50S rRNA基因的18.3%(11/60)。本试验为猪支原体病的诊断及流行病学调查提供了更为敏感、特异的检测技术。     

3种PCR引物对猪瘟活疫苗中支原体污染的检测

本研究以GenBank中登录的几种常见支原体的16S rRNA基因序列为标准,依据其属、种特征设计了3对引物,对猪肺炎支原体DNA进行PCR扩增,建立PCR扩增体系和条件。然后以此体系和条件对从市场上随机购买的猪瘟活疫苗样品进行检测。结果显示：3对PCR引物都可以从疫苗样品中检测到支原体的污染,3对引物的检出率分别为20%、17.1%和14.3%,说明猪瘟活疫苗中的支原体污染为多种支原体的混合污染,污染源较为复杂。     

副猪嗜血杆菌PCR检测方法的建立与应用

为了快速检测临床上副猪嗜血杆菌(Haemophilus parasuis,Hps)感染,根据Gen Bank中Hps的16S rRNA基因保守区序列,设计1对特异性引物,利用PCR方法检测Hps,并进行特异性、敏感性及临床检测。结果显示:PCR反应选择58℃为最适退火温度,0.5μL(20μmol/L)为最适引物量,模板浓度为7.2×10~(-6)μg/mL时即可扩增出814 bp特异性目的片段,与细菌分离结果一致。结果表明:该方法敏感、快速、特异,可用于临床上Hps感染的快速检测。     

猪附红细胞体单管巢式PCR诊断方法的建立及应用

根据GenBank上发表的猪附红细胞体16S rRNA基因序列(登录号U88565)设计合成2对引物,建立了猪附红细胞体单管巢式PCR诊断方法,经酶切分析、单管巢式PCR进一步鉴定后进行序列测定,并与血涂片染色镜检、常规PCR进行了比较。结果:扩增的猪附红细胞体基因序列与GenBank中发表的猪附红细胞体基因序列(U88565)同源性为96%;特异性试验表明,设计的引物不能扩增弓形虫、链球菌、大肠杆菌、葡萄球菌及羊附红细胞体等病原体;敏感性试验表明,单管巢式PCR诊断方法最低能够检测出0.116 fg的标准模板DNA。通过对75份血液样本的检测表明,建立的单管巢式PCR方法明显优于血涂片染色镜检法及常规PCR方法,具有较高的敏感性和实用性。本试验建立的单管巢式PCR诊断方法具有特异、敏感、实用等优点,为猪附红细胞体的检测提供了一种新型、可靠的诊断技术。     

PCR方法诊断猪瘟病毒和猪丹毒杆菌混合感染

应用PCR快速检测急性病死猪的病原.采集病死猪脾等组织,用PCR方法检测猪繁殖与呼吸综合征病毒(PRRSV)、猪瘟病毒(CSFV)和猪圆环病毒2型(PCV-2).同时采集病死猪肝、心血,无菌接种血平板进行细菌分离,用16 S rRNA基因测序法鉴定分离菌.对分离菌株进行药敏试验.PCR检测结果显示检测样品用CSFV引物...     

猪关节病重要病原体多重PCR检测方法的建立及应用

为了同时检测引起猪关节病的猪链球菌2型(Streptococcus suis type2,SS2)、副猪嗜血杆菌(Haempohlius parasuis,HPS)和猪丹毒丝菌(Erysipelothrix rosenbach),分别设计针对SS2的cps2J基因、HPS和猪丹毒丝菌的16S rRNA基因的3对特异性引物,建立了同时检测以上3种病原的多重PCR方法,并对反应条件进行优化,测试多重PCR方法的特异性和灵敏度。对采自8个规模猪场的猪关节病病料进行检测,从72份猪关节液样品中检出2株猪链球菌2型、1株副猪嗜血杆菌和2株猪丹毒丝菌,结果显示与常规PCR检测结果一致,表明建立的多重PCR方法敏感、特异、快速,可用于猪关节病重要病原体的检测。     

兔多杀性巴氏杆菌16S rRNA PCR检测方法的建立

为建立一种快速准确检测兔多杀性巴氏杆菌(P.multocida)的PCR方法,本研究以P.multocida的高度保守的16S rRNA为靶基因,参考已公布的P.multocida的16S rRNA基因设计1对特异性引物,优化PCR反应条件,建立了P.multocida PCR快速检测方法。该PCR方法的敏感性达到60 cfu/mL,采用该PCR方法扩增P.multocida标准株和分离株均能扩增出643 bp的目的片段,扩增兔大肠杆菌、支气管败血波氏杆菌结果为阴性,证明本实验所建立的P.multocida PCR检测方法快速、敏感、特异、可靠,可用于P.multocida的快速鉴定与诊断。同时用建立的PCR方法对临床疑似病兔的脏器分离菌进行扩增,可扩增出目的条带,与细菌的分离结果相一致。     

Detection and quantitation of Ehrlichia risticii genomic DNA in infected horses and snails by real-time PCR

A real-time quantitative PCR using the TaqMan fluorogenic detection system (TaqMan PCR) was established for identification of Ehrlichia risticii, the agent of Potomac horse fever (PHF). The TaqMan PCR identified an 85 base pair section of the 16S rRNA gene by use of a specific fluorogenic probe and two primers. This technique was specific for eight tested E. risticii strains. The TaqMan system identified 10 copies of a cloned section of the 16S rRNA gene of E. risticii. The sensitivity and specificity of the TaqMan PCR were similar to those of conventional nested PCR. The TaqMan PCR was evaluated on horses with infectious colitis and on freshwater stream snails collected from regions with a history of PHF. E. risticii could be detected in 22 of 153 (14.4%) horses with infectious colitis and in 25 of 234 (10.7%) snails in the TaqMan PCR. The same results were obtained in the conventional nested PCR. The Ehrlichia-load was in the range of 10,000-9,000,000 and 35,000-680, 000,000 Ehrlichia equivalents per microg leukocyte DNA and snail DNA, respectively.     

Real-time PCR for detection and differentiation of Streptococcus equi subsp. equi and Streptococcus equi subsp. zooepidemicus

Strangles is a contagious equine disease caused by Streptococcus equi subsp. equi. In this study, clinical strains of S. equi (n=24) and Streptococcus equi subsp. zooepidemicus (n=24) were genetically characterized by sequencing of the 16S rRNA and sodA genes in order to devise a real-time PCR system that can detect S. equi and S. zooepidemicus and distinguish between them. Sequencing demonstrated that all S. equi strains had the same 16S rRNA sequence, whereas S. zooepidemicus strains could be divided into subgroups. One of these (n=12 strains) had 16S rRNA sequences almost identical with the S. equi strains. Interestingly, four of the strains biochemically identified as S. zooepidemicus were found by sequencing of the 16S rRNA gene to have a sequence homologous with Streptococcus equi subsp. ruminatorum. However, they did not have the colony appearance or the biochemical characteristics of the type strain of S. ruminatorum. Classification of S. ruminatorum may thus not be determined solely by 16S rRNA sequencing. Sequencing of the sodA gene demonstrated that all S. equi strains had an identical sequence. For the S. zooepidemicus strains minor differences were found between the sodA sequences. The developed real-time PCR, based on the sodA and seeI genes was compared with conventional culturing on 103 cultured samples from horses with suspected strangles or other upper respiratory disease. The real-time PCR system was found to be more sensitive than conventional cultivation as two additional field isolates of S. equi and four of S. zooepidemicus were detected.     

Broad range 16S rRNA gene PCR compared to bacterial culture to confirm presumed synovial infection in horses

The objectives of the present study were to evaluate the accuracy of broad range 16S rRNA gene PCR compared to bacterial culture for the detection of synovial infection in horses. The study included 57 synovial fluid samples from horses with presumed synovial infection and a control group consisting of 31 synovial fluid samples originating from clinically normal horses and horses with aseptic synovial inflammation. All samples were analysed by 16S PCR with reverse line blot (RLB) hybridisation. Synovial fluid samples were cultured using conventional agar plate methods (APM) and/or blood culture medium (BCM). The results of the study showed a superior detection rate (89.5%) for 16S PCR with RLB. Bacterial culture had lower sensitivity, but highly acceptable detection rates (77.6%) were observed using BCM. APM had very low sensitivity (37.8%) and infection was never detected by plate isolation without positive incubation in BCM. The highest sensitivity (91.8%) for the detection of synovial infection was achieved when the results of incubation in BCM and 16S PCR were combined. For all the tests, the specificity was higher than 90%.     

检测伪狂犬病毒gB基因荧光定量PCR方法的建立

利用DNAMAN软件对GenBank登录的伪狂犬病病毒（PRV）各毒株gB基因序列进行比对分析,选择其保守区域设计合成特异性的引物和TaqMan探针,同时利用普通PCR技术扩增获得全长的伪狂犬病毒gB基因,并克隆到pMD20-T载体上作为阳性标准品。通过对荧光定量PCR反应条件的优化,建立了一种快速检测伪狂犬病病毒的荧光定量PCR技术。该检测技术具有较高的灵敏性、特异性和可靠性。对制备的pMD-gB阳性标准品的检测结果表明,所建立的伪狂犬病毒TaqMan荧光定量PCR最低检测极限可达1.50×102拷贝/反应;同时相比于普通PCR方法其灵敏度高100～1 000倍以上,并且重复性好。在对60份临床样品的检测中,荧光定量PCR不仅检出了普通PCR检测为阳性的样品,且检出了2份普通PCR未检出的样品,进一步证实了该方法快速、灵敏性好,可用于PRV感染的早期快速定量检测和肉类食品进出口检疫。     

Molecular identification of `Candidatus Mycoplasma haemovis' in sheep with hemolytic anemia

We examined the presence of hemoplasmas, hemotropic mycoplasmas, among 11 sheep (Ovis aries) with regenerative and hemolytic anemia and found six of them were positive by real-time PCR. The positive samples were then subjected to conventional PCR for direct sequencing of the 16S rRNA gene. Nucleotide sequences of all the positive samples were identified as the 16S rRNA gene of `Candidatus Mycoplasma haemovis' by phylogenetic analysis, demonstrating the infections with this particular hemoplasma species in Japan.     

羊泰勒虫不同PCR检测方法的比较

为寻求快速、有效检测羊泰勒虫的PCR方法,本试验建立了检测羊泰勒虫18SrRNA基因和表面蛋白基因的两种常规PCR方法和一种检测18SrRNA基因的半套式PCR方法,并从其敏感性和临床样本检出率等方面进行了比较。结果显示:上述方法检测羊泰勒虫基因组DNA的最小检测量分别为1.6fg/μL、16fg/μL和0.016fg/μL;检测临床样本阳性检出率分别为31.37%(16/51)、17.64%(9/51)和45.10%(23/51)。3种方法中,检测18SrRNA基因的半套式PCR方法敏感性和临床样本检出率最高,其次为检测18SrRNA基因的常规PCR方法,最后为检测表面蛋白基因的常规PCR方法。结果说明,所建立的半套式PCR方法是一种较好的羊泰勒虫检测方法。     

Mycoplasma ovis detected in free-living Japanese serows, Capricornis crispus

Nineteen blood samples collected from free-ranging wild Japanese serows, Capricornis crispus, between 2006 and 2008 in Iwate prefecture were examined for the hemoplasma infection by real-time PCR targeting the 16S rRNA gene. Five (26.3%) out of the 19 samples were positive in real-time PCR with an average melting temperature at 85.18 °C. The positive samples in the real-time PCR were reconfirmed by conventional PCR, and one of them was successful for direct DNA sequencing. The nucleotide sequence of the 16S rRNA gene of the representative stain was identical to that of Mycoplasma ovis. This was the first demonstration of hemotropic mycoplasma infections among the free-living Japanese serows in Japan.     

鼠源细胞TaqMan实时荧光定量PCR检测方法的建立

为对鼠源细胞进行鉴别检测,以鼠线粒体16S rRNA基因序列为靶位点设计特异性引物及探针,建立实时荧光定量PCR检测方法,并评价该方法的特异性及敏感性。结果显示,所建立的检测方法特异性好,针对鼠源细胞基因组荧光定量PCR扩增曲线良好,其他物种来源细胞基因组及生物制品原辅材料未出现特异性扩增曲线;敏感性高,基因拷贝数检出限度为45.3拷贝。本试验建立的荧光定量PCR检测方法能够有效地对鼠源细胞进行快速检测,为细胞质量控制提供了有效方法。     

动物园野生动物支气管败血波氏杆菌的分离鉴定与系统发育树的构建

采用Biolog和16SrRNA基因序列分析法对分离自北京动物园的8株支气管败血波氏杆菌进行了鉴定。菌株经纯化培养,用Biolog微生物鉴定系统进行了鉴定,结果表明,8株菌株为支气管败血波氏杆菌。菌株经纯化培养,采用菌落PCR方法进行16SrRNA基因序列扩增,扩增产物纯化后直接进行测序。序列经人工校对后用ClustalX1.83软件进行比对分析,最后用Mega3.1软件构建系统发育树,系统发育分析结果表明,8株菌株与支气管败血波氏杆菌DSM10303的同源性达到了99.9%,并在同一个分支内。