HBV-HCV-HIV三联荧光PCR检测的内标浓度选择研究

目的 选择一个在乙型肝炎病毒-丙型肝炎病毒-人类免疫缺陷病毒（HBV—HCV—HIV）三联荧光PCR检测试验中既可有效监控假阴性结果出现，又对阳性结果影响最小的内标浓度。方法应用不同浓度的内标参入酶链聚合反应（PCR）反应，确定最佳内标参人量；并在适量内标浓度下，检测低浓度标本的阳性检出率。结果由内标浓度5拷贝／PCR、10拷贝／PCR、20拷贝／PCR、50拷贝／PCR、100拷／PCR5个浓度中，优选出最适的内标浓度为20拷贝／PCR，此条件下，阴性标本的内标检出率为100％，检测灵敏度标本的阳性检出率与无内标样本差异无统计学意义。结论合适浓度的内标参与荧光PCR检测能有效地解决了每个标本的质控问题，指示反应体系（试剂耗材）与检测体系（仪器）的有效性。     

两种方法检测HCV-RNA的结果分析

目的比较两种方法检测丙型肝炎病毒核酸(HCV-RNA)的结果。方法逆转录套式定性PCR(RT-nestedPCR)和荧光定量PCR对288例抗-HCV阳性的丙型肝炎患者血清标本进行HCV-RNA检测。结果288例抗-HCV阳性血清标本有248例RT-nested-PCR结果阳性,阳性率为86.1%(248/288);226例荧光定量PCR检测HCV-RNA>103拷贝/ml,检出率为78.5%(226/288),两种检测结果的阳性符合率为85.9%(219/255)。同时,29例标本定性结果阳性,定量结果<103拷贝/ml;7例标本定性结果阴性,定量结果>103拷贝/ml,差异具有统计学意义(χ2=12.25,P<0.01)。结论两种方法检测HCV-RNA,可以提高检测的灵敏度,为临床治疗提供依据。     

核酸血液筛查试剂内标质控效果研究

目的竞争性内标对核酸检测灵敏度的影响程度及方式,探寻采用适度的内标质控浓度,用于有效控制核酸检测过程。方法使用竞争性混合内标试剂对不同浓度的HBV、HCV、HIV阳性标本检测,HBV内标浓度<103IU/ml,HCVt HIV内标浓度为(200—300)IU/ml。结果HBV内标浓度<5IU/ml检出率<95%,浓度>10IU/ml后检出率≥95%,HCV、HIV内标浓度<100IU/ml检出率<95%,≥100IU/ml检出率≥95%。结论内标(内参照)把质量控制从每批阳性质控提高到每管阳性质控的水平,能有效减少假阴性检测结果,竞争性内标结构和待检物几乎完全相同,更能真实反应情况。     

基于MGB探针法荧光PCR检测手足口病病原的研究

目的建立一种能同时检测EV71型、CA16型及其它肠道病毒的荧光PCR检测方法,主要用于手足口病病原的快速检测。方法针对肠道病毒的保守基因设计特异性引物和探针序列,优化荧光RT-PCR反应体系,构建标准的阳性质控模板,建立标准曲线,研究产品的检测限、重复性、特异性;同时对2015年6月份收集的26份阳性样品和10份阴性样品进行检测。结果试验得到了阳性重组质粒,线性范围在8×10~2 copies/μl~8×10~8 copies/μl范围内检测结果良好;优化后肠道病毒EVUN上下游引物和MGB探针浓度分别为0.50,0.50,0.30μmol/L,RT-PCR反应条件为:42℃30min,95℃3min;95℃5s,60℃35s,45个循环。检测限达到800copies/μl,变异系数CV≤5%,重复性好,特异性良好,与其他传染病毒无交叉反应;用该检测方法检测26份临床阳性样本和10份阴性样本,阳性检出率为100%(26/26),阴性检出率为100%(10/10)。结论试验所建立的荧光PCR检测方法,可用于临床对手足口病病原的快速检测。     

超敏HBV DNA定量检测系统的临床应用研究

目的:比较超敏HBV DNA检测系统与传统荧光定量PCR外标法定量检测血清乙肝病毒DNA,探讨其临床应用价值。方法:采用超敏PCR检测系统和传统荧光定量PCR外标法同时检测80例HBsAg阳性患者的血清HBV DNA浓度。结果:超敏法阳性检出率(92.5%)高于传统外标法(50.0%)(P0.01)。超敏法阳性定量结果中位值为2.95×10~5IU/mL,高于传统外标法(5.63×10~4IU/mL)(P0.01),两种方法对高载量病毒(≥10~4IU/mL)血清标本检测结果的相关性有统计学意义(R~2=0.89,P0.01)。超敏法对26例HBeAg阴性慢性乙肝患者的阳性检出率(100.0%)高于传统外标法(11.5%)(P0.01)。结论:超敏HBV DNA定量检测系统检测灵敏度高,更适用于临床低载量病毒(10~4IU/mL)血清标本的检测。     

实时荧光PCR检测结核杆菌DNA的分析灵敏度验证及临床应用

目的以结核杆菌DNA检测为切入点,建立实时荧光PCR定性方法分析灵敏度验证的方法并进行评价。方法取5个低浓度标本分别平行检测16次,计算每个标本的检出率,分别以浓度的对数(以10为底)、Ct值和检出概率作曲线拟合,得到结核杆菌DNA荧光PCR检出率为50%和95%所对应的浓度及Ct值,并据此建立结果报告策略。以巢式PCR和实时荧光PCR同时检测52例临床标本,评价所建立的结果报告策略的适用性。结果结核杆菌DNA检出率为50%和95%所对应的浓度分别为69copy/mL,2.46×10~3 copy/mL。所建立的结果报告策略为结果大于2.46×10~3 copy/mL时报告阳性,结果小于2.46×10~3 copy/mL而大于69copy/mL时进行复查,如果复查为阳则报告阳性,如果复查结果为阴性时报告为阴性,结果小于69copy/mL报告为阴性。52例临床标本经检测后,荧光PCR检出6例阳性,巢式PCR检出4例阳性,计算kappa值经u检验(kappa=0.78,u=3.58,P0.05)表明两种方法报告的结果具有良好的一致性。结论依据检出概率-浓度曲线制定结核杆菌-DNA荧光PCR定性方法结果报告策略具有较好的临床适用性,依据最低检出限制订结果报告策略可应用于基于定量数据的定性PCR。     

实时荧光定量PCR快速检测脑膜炎奈瑟菌的临床价值

目的探讨实时荧光定量聚合酶链反应(PCR)快速检测流行性脑脊髓膜炎(简称流脑)病原菌脑膜炎奈瑟菌(Nm)的临床价值。方法收集70例疑似流脑病例的双份脑脊液标本,1份采用细菌培养法进行检测,另1份采用实时荧光定量PCR进行检测,比较2种方法的检出阳性率以及敏感性和特异性。结果采用细菌培养法检出Nm阳性49例,阳性率为70.00%;实时荧光定量PCR检出Nm阳性67例,阳性率为95.71%,二者阳性率比较差异有统计学意义(P0.05)。实时荧光定量PCR检测结果与细菌培养法阳性符合率为70.00%,其中有18例细菌培养法为阴性而实时荧光定量PCR为阳性。实时荧光定量PCR检测Nm的特异性为100%,无假阴性结果,阳性预测值为73.13%,阴性预测值为0.00%,检测下限为103拷贝/m L,线性范围为2×103~2×107拷贝/m L。结论实时荧光定量PCR检测Nm敏感性高、特异性强,且快速简便,为流脑流行病学调查提供了一种快速、简便的病原学诊断手段。     

SYBRGreen荧光定量PCR检测HTLV-I前病毒tax基因方法的建立

目的建立HTLV—I前病毒tax基因的荧光定量PCR检测方法。方法根据HTLV—Itax基因序列设计引物，将PCR克隆的tax片段链接入质粒载体，经筛选鉴定后，以含有目的片断的质粒为阳性模板建立实时荧光定量检测方法。结果扩增体系的敏感度可达10拷贝／反应。模板浓度在10^5～10^1拷贝／反应时，模板浓度与循环闽值（Q）之间相关性良好，相关系数r=-0，9987，且模板浓度相同的反应管之间具有良好的重复性和稳定性。结论SYBRGreen荧光定量PCR检测HTLV—I前病毒tax基因方法具有简便、快速和灵敏度高等优点，可能在疾病诊断、监测以及血液筛查中具有一定的应用前景。     

荧光定量PCR分析法在结核病诊断中的应用

为了探讨荧光定量PCR(FQ PCR)技术检测结核分枝杆菌的临床应用 ,本文采用FQ PCR技术检测 14 5例标本 ,并与培养法、抗酸染色法和PCR 电泳法进行比较。结果 :在 115例来自结核病人的高度怀疑有结核分枝杆菌的标本中 ,FQ PCR法检出阳性为 5 3例 ,其检出率高于PCR 电泳法检出率(4 8/ 115 )、培养法检出率 (4 3/ 115 )和抗酸染色法检出率 (31/115 ) ,30例非结核病的病人标本 ,四种方法均未检出结核分枝杆菌。FQ PCR法的阳性检出最低值为 10 3 拷贝 /ml,PCR 电泳法为 10 4拷贝 /ml。结果表明 ,FQ PCR技术是高度灵敏、高度特异的快…     

联检反应性鉴别非反应性献血者血浆标本乙型肝炎病毒感染情况的研究

目的 分析常规血筛中核酸单检系统联检结果反应性而初次鉴别结果非反应(NRR)献血者标本中HBV的感染情况,以期为NRR标本后续相关研究提供建议及数据支持。方法 对60份常规血筛中酶免结果阴性,核酸单检系统检测结果为NRR的献血者血浆标本进行HCV RNA和HIV RNA重复鉴别检测、HBV DNA病毒载量检测、HBV pgRNA病毒拷贝量检测,并对HBV DNA病毒载量和HBV pgRNA病毒拷贝量检测结果为阳性的NRR标本进行HBsAg、HBsAb、HBcAb、HBeAg、HBeAb的血清学检测,分析其中血清学感染状态和隐匿性乙型肝炎(OBI)的感染情况。结果 60份NRR标本HCV RNA及HIV RNA重复鉴别结果均为阴性。60份NRR标本中HBV DNA定量检测结果为阳性的有9份(15%),HBV DNA浓度均<10 IU/mL;HBV pgRNA定量检测结果为阳性的有9份(15%),其病毒拷贝量■为289±58.25(copies/mL);HBV DNA阳性且HBV pgRNA阳性NRR标本有2份(3.33%)。9份HBV DNA阳性标本中HBcAb阳性率最高为66.6...     

建立实时荧光LAMPA法检测肺炎支原体

目的:建立实时荧光环介导等温扩增(LAMP)法检测肺炎支原体。方法:在LAMP体系中添加适量荧光染料SYTO-9,通过实时定量PCR仪监测LAMP反应结果。以肺炎支原体P1基因重组质粒制备一系列浓度标准品,分别使用实时荧光LAMP法和SYBR GreenⅠ染料LAMP法检测,比较2种方法的检出限。肺炎支原体M129标准株菌液以10倍梯度稀释,分别以实时荧光LAMP法和肺炎支原体荧光PCR试剂盒检测,比较2种方法灵敏度。以实时荧光LAMP法检测常见呼吸道感染病原体肺炎链球菌、金黄色葡萄球菌、表皮葡萄球菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌和大肠埃希菌基因组DNA,评估该方法特异性。采集疑似肺炎支原体感染患儿咽拭子标本,分别以实时荧光LAMP法和荧光PCR法检测,比较2种方法检出率差异。结果:实时荧光LAMP法可以检出P1基因最低限为103 copies/μL,当基因拷贝数大于104 copies/μL时,反应30 min样本组即可出现明显荧光信号。SYBR GreenⅠ染料LAMP法可以检出P1基因最低限为104 copies/μL,反应需1 h才可获得足够产物用于显色。实时荧光LAMP法灵敏度高于实时定量PCR法100倍,且对常见呼吸道病原体DNA无扩增。实时荧光LAMP法和荧光PCR法检测疑似肺炎支原体感染咽拭子标本的阳性率差异无统计学意义(P>0.05)。结论:实时荧光LAMP法可以有效避免因开盖检测造成的气溶胶污染,反应时间短,灵敏度高,适于在基层医院中推广使用。     

Development of an internal control for the detection of the African swine fever virus by PCR

For the detection of African swine fever virus (ASFV) by polymerase chain reaction (PCR) in clinical samples, an internal control was constructed to identify false negative results in each reaction. The internal control was designed in such a way that the same primer pair was used to amplify the internal control and the target DNA which were differentiated by size. The lower detection limit was reached at about 30 internal control DNA copies and about 50 genomic ASFV DNA copies. The use of the internal control revealed that from a total of 12 uninfected samples, 10 samples contained inhibitors. After a one in two dilution, all ten of these samples amplified the internal control satisfactorily. From a total of 16 samples from pigs suspected of having ASF infection, nine contained inhibitors. After a one in two dilution, we observed internal control amplification and target DNA amplification for four samples.     

Rapid and reliable genotyping of HLA-B*27 in the Chinese Han population using a duplex real-time TaqMan PCR assay

ObjectivesTo develop a duplex real-time TaqMan PCR assay for genotyping HLA-B*27 in the Chinese Han population.Design and methodsA standard curve was constituted to deduce amplification efficiency, dynamic range and detection limit of the duplex real-time TaqMan PCR assay, whereas PCR-SBT (PCR with sequence-based typing) was used to evaluate the accuracy of the assay.ResultsA linear standard curve for determining HLA-B*27 was obtained within the range of 10¹–10⁹ copies per reaction with the correlation coefficient of 0.99 and amplification efficiency of 98.30%. The detection limit was 3.09 copies per reaction. Complete concordance was found between the results obtained by the duplex real-time TaqMan PCR assay and PCR-SBT. Fifty-nine of the 178 genomic samples were HLA-B*27 positive and the other 119 were HLA-B*27 negative.ConclusionsThe duplex real-time TaqMan PCR approach appears to be a reliable, sensitive, rapid and high-throughput method to genotype HLA-B*27 in the Chinese Han population.     

EV71-CA16肠道病毒荧光定量RT-PCR诊断试剂盒的研制

目的研制一种能同时检测EV71,CA16肠道病毒的二联实时荧光定量PCR检测试剂盒,主要用于EV71,CA16肠道病毒的快速检测和流行病学监测。方法设计特异度的EV71型、CA16型基因的引物和探针,优化实时荧光定量PCR检测体系,并研究产品的灵敏度、精密度、稳定性和检测线性范围;同时对2014年5月份收集的26份样品进行检测。结果试验得到了阳性重组质粒,线性范围在5*102 copies/μl～105 copies/μl,该范围内检测结果良好;优化后肠道病毒CA16上下游引物和探针浓度分别为0.48,0.24μmol/L,EV71上下游引物和探针浓度分别为0．40,0.20 μmol/L。敏感度达到500 copies/μl,重复性变异系数CV≤5％;该荧光定量PCR检测试剂盒稳定性强,在-20℃下可以保存一年,对EV71,CA16肠道病毒具有良好的特异度。用该方法检测20份临床阳性样品和6份阴性样品,阳性检出率为100％(20/20),阴性检出率为100％(6/6)。结论试验建立的EV71,CA16肠道病毒实时荧光定量RT-PCR检测方法可用于EV71,CA16肠道病毒的临床诊断。     

Evaluation of a new multiplex polymerase chain reaction assay STDFinder for the simultaneous detection of 7 sexually transmitted disease pathogens

We evaluated a new multiplex polymerase chain reaction (mPCR), “STDFinder assay”, a novel multiplex ligation-dependent probe amplification (MLPA) assay for the simultaneous detection of 7 clinically relevant pathogens of STDs, i.e., Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Mycoplasma genitalium, Treponema pallidum, and herpes simplex virus type 1 and 2 (HSV-1 and HSV-2). An internal amplification control was included in the mPCR reaction. The limits of detection for the STDFinder assay varied among the 7 target organisms from 1 to 20 copies per MLPA assay. There were no cross-reactions among any of the probes. Two hundred and forty-two vaginal swabs and an additional 80 specimens with known results for N. gonorrhoeae and C. trachomatis, obtained from infertile women seen at an infertility research clinic at the Kigali Teaching Hospital in Rwanda, were tested by STDFinder assay and the results were confirmed by single real-time PCR using different species-specific targets. Compared to the reference standard, the STDFinder assay showed specificities and sensitivities of 100% and 100%, respectively, for N. gonorrhoeae, C. trachomatis, and M. genitalium; 90.2% and 100%, respectively, for Trichomonas vaginalis; and 96.1% and 100%, respectively, for HSV-2. No specimen was found to be positive for HSV-1 by either the STDFinder assay or the comparator method. Similarly, the sensitivity for Treponema pallidum could not be calculated due to the absence of any Treponema pallidum-positive samples. In conclusion, the STDFinder assays have comparable clinical sensitivity to the conventional mono and duplex real-time PCR assay and are suitable for the routine detection of a broad spectrum of these STDs at relatively low cost due to multiplexing.     

Real-time polymerase chain reaction for detection of Isospora belli in stool samples

A real-time polymerase chain reaction (PCR) assay targeting the internal transcribed spacer 2 region of the ribosomal RNA gene was developed for the detection of Isospora belli DNA in fecal samples, including an internal control to detect inhibition during the amplification process. The assay was performed on species-specific DNA controls (n = 27) and a range of positive (n = 21) and negative (n = 120) stool samples, and achieved 100% specificity and sensitivity. The simple fecal sample collection procedure, the high-throughput potential, and the possibility of quantification makes the I. belli real-time PCR assay a powerful diagnostic tool for epidemiologic studies with possibilities for extension to other helminthes and protozoa using additional molecular targets. In addition, this Isospora PCR could augment the clinical laboratory diagnosis of isosporiasis, in particular, in patients with a travel history to developing countries.     

Development of a PCR-based method coupled with a microplate colorimetric assay for the detection of Porcine Parvovirus and application to diagnosis in piglet tissues and human plasma

A new method for Porcine Parvovirus (PPV) diagnosis was developed. The method is based on polymerase chain reaction (PCR) amplification followed by hybridization and colorimetric detection of PCR products in microwell plates. A highly specific and sensitive amplification step was ensured by primers carefully selected in the VP2 structural gene and optimized PCR conditions. Uracyl-DNA-Glycosylase (UDG) in combination with dUTP was used to avoid false-positive results, and 100 copies of internal control (IC) were added to each PCR reaction to reveal any false-negative samples. Biotinylated amplified fragments were hybridized on specific capture probes covalently linked to microwell plates. Finally, the detection of hybridized PCR products was performed by means of a colorimetric reaction, which was automated. The method permitted the detection of 10³copies (6 fg) of replicative form DNA (RF-DNA) in 20 mg of lung sample, and 500 copies (3 fg) in 100μl of plasma. It was used to analyse 24 field piglet tissue samples, and 35 human plasma or serum specimens collected from patients treated with porcine Factor VIII concentrates.     

IgH重排的实时定量PCR检测及反应参数研究

为了探讨以通用引物应用PCR技术扩增克隆性免疫球蛋白重链基因（IgH）重排的最佳实验条件及SYBR Green Ⅰ实时定量PCR检测该基因的可行性，以通用引物对克隆性IgH重排进行扩增，对影响PCR扩增的退火温度、引物浓度、Taq酶用量、dNTP浓度、镁离子浓度、循环次数等实验因素进行了系统研究，找出最佳反应参数。并以通用引物进行了SYBR greenⅠ实时定量PCR对IgH重排基因的检测，测定了该法检测IgH重排基因的敏感性。结果表明：最佳退火温度为60℃，最佳引物浓度为0．8μmol／L，0．5U的Taq酶量效果满意，最适dNTP浓度为100μmol／L，最适镁离子浓度为3．0mmol／L，最佳循环次数为40次。SYBR GreenⅠ实时定量PCR可以实现对克隆性IgH重排的扩增和荧光信号的检测分析，其对IgH重排基因检测的敏感性为10^4／ml。结论：确定了应用PCR技术检测克隆性IgH重排的最适反应条件，实现了用通用引物对克隆性IgH重排稳定、特异的扩增，初步实现了以通用引物和应用SYBR Green Ⅰ实时定量PCR对IgH重排的检测。     

焦磷酸测序法在幽门螺杆菌克拉霉素耐药基因检测及药物疗效评价中的应用

目的本研究建立了幽门螺杆菌(Hp)克拉霉素耐药基因检测的焦磷酸测序方法,在获知耐药情况的同时根据半定量结果初步评估治疗效果。方法通过考察最合适的扩增引物、体系、退火温度建立最优的PCR扩增体系。分别对方法的灵敏度,特异性及一致性进行了评价。通过对44例临床标本的检测,比较本方法与快速尿素酶试验和13 C呼气试验的检出率。结果最优的PCR扩增体系为HiFi体系,最佳退火温度为59.8℃。本方法特异性良好,灵敏度达到100 copies/μL,与Sanger测序结果100.0%一致。36例标本快速尿素酶和焦测序法的检出率分别为48.7%和81.1%,耐药率为10.81%。8例标本13 C呼气试验和焦测序法的检出率分别为75.0%和87.5%,阳性标本检出一致率为100.0%。结论焦测序检测方法具备灵敏度高、快速、半定量的特点,为临床Hp克拉霉素耐药检测及初步疗效评价提供了一种新的方法。     

Development of a semiquantitative PCR assay using internal standard and colorimetric detection on microwell plate for pseudorabies virus

We have developed a semiquantitative PCR assay on microtitre plates for quantitation of pseudorabies virus (PRV). The test is based on co-amplification with an internal control (IC) of the target viral DNA, followed by hybridization of the biotin-amplified products on a capture probe covalently immobilized to a Covalink-NH MicroWells plate and then visualization with colorimetric enzymatic reactions. PCR was performed in the presence of uracil-N-glycolsylase (UNG) with dUTP instead of dTTP to prevent false positive results due to carry-over contamination. Our colorimetric test had a 3·5 log dynamic range with a detection level of 30 DNA copies per PCR reaction. A standard curve for quantitation of pseudorabies virus was established from co-amplification of 10 to 10⁵PRV molecules with 1000 IC molecules. Ratios of viral optical density/IC optical density were plotted against the number of PRV DNA target molecules in the PCR amplification. Integration of 96-well formats and automation using robots at different steps of the test ensured a good repeatability. Calibration of the quantitative test using samples from experimentally-infected pigs is in progress.