多重实时PCR检测沙门菌、志贺菌和致泻性大肠埃希菌

目的 建立多重实时荧光PCR检测沙门菌侵袭蛋白A基因（invA）、肠产毒性大肠埃希菌（ETEC）不耐热肠毒素基因（elt）、志贺菌和肠侵袭性大肠埃希菌侵袭力基因（ipaH）的方法。方法 优化多重实时荧光PCR的反应条件,检测系列10倍稀释的阳性菌DNA提取物。90份腹泻患者粪便样品经缓冲蛋白胨水（buffered peptone water,BP）增菌6h后进行多重实时荧光PCR检测,并对阳性标本进行菌株分离和鉴定。结果 多重实时PCR方法最低可以检测到10CFU／μl的福氏2aF301株、10。CFU／μl的鼠伤寒沙门菌和ETEC44815株。检测腹泻患者粪便样品,elt基因阳性率为14．4％（13／90）,ipaH基因阳性率为5．6％（5／90）;并从阳性样品中分离到3株elt基因阳性大肠埃希菌和4株ipaH基因阳性大肠埃希菌。整个检测过程可在10h内完成,其中包括BP增菌6h。结论 建立了同时检测invA、elt、ipaH毒力基因的多重实时荧光PCR方法,具有高度的特异性,可用于沙门菌、肠产毒性大肠埃希菌、志贺菌和肠侵袭性大肠埃希菌菌株的毒力基因鉴定及临床腹泻粪便标本的快速筛检。     

云南省保山市人间狂犬病调查及病毒分子生物学特征分析

目的 了解云南省保山市发生2例狂犬病患者的流行病学特点,根据病原分子生物学特征分析可能的传染来源.方法 采用狂犬病个案调查表进行流行病学调查,采集狂犬病死者脑组织标本,用直接免疫荧光试验(DFA)检测狂犬病病毒抗原,用RT-PCR法检测狂犬病病毒核酸,测定狂犬病病毒P、M和N基因全序列并根据其同源性比较及系统进化树进行分子流行病学分析.结果2006年7月保山市隆阳区发生1例人间狂犬病,2007年4月腾冲县发生1例狂犬病.2例患者犬伤暴露程度均为Ⅲ度.2例死亡病例均采集到脑组织(编号为CYN0601H和CYN0701H),经DFA和RT-PCR两种实验室方法检测确诊为狂犬病病毒阳性.CYN0601H和CYN0701H与国内外狂犬病病毒的P、M和N基因核苷酸和推导氨基酸序列同源性分析显示,CYN0601H和CYN0701H与泰国分离株的同源性最高.系统进化分析显示,2株病毒标本亲缘关系很近,同属于狂犬病病毒基因1型,且与泰国病毒株有较近的亲缘关系.结论从病原学和病毒分子水平证实云南省保山市2例患者均为狂犬病,保山市狂犬病病毒流行株可能为境外传人,应加强云南省边境地区狂犬病防制工作.     

Development and evaluation of a real-time FRET probe based multiplex PCR assay for the detection of prohibited meat and bone meal in cattle feed and feed ingredients

A novel real-time fluorescent multiplex polymerase chain reaction (PCR) assay for detecting and discriminating between bovine, ovine, and caprine contaminates in cattle feed was developed that simultaneously performs quality control monitoring on both the DNA extraction process and the level of PCR inhibition in the final DNA extract in a single PCR run. The assay used a single set of primers and two sets of FRET probes targeting the ruminant-specific mitochondrial cytochrome b gene. An internal control PCR reaction targeting a region of the chloroplast RNA polymerase beta-subunit (rpobeta) gene, which is conserved among plants, was incorporated into the ruminant multiplex PCR reaction in order to both monitor the DNA extraction method and to test for the presence of PCR inhibitors. The detection limit for bovine and ovine contaminates was evaluated over a period of two sets of six trials on 15 different types of cattle feed and feed ingredients spiked with known concentrations of bovine meat and bone meal (BMBM) and lamb meat and bone meal (LMBM). The assay was able to detect 0.05% w/w BMBM contamination and 0.1% w/w LMBM contamination in all samples of cattle feed and feed ingredients tested.     

多重PCR快速检测食品中肠出血性大肠杆菌

本研究建立了一种快速检测食品中肠出血性大肠杆菌 (EHEC)的多重PCR方法。将样品增菌后 ,采用快速裂解吸附法制备模板 ,用多重PCR同时检测EHEC的三种毒力基因eaeA、hlyAB、slt1 2 ,相应扩增片段依次为 110 9、30 2、2 2 8bp。检测了 6 0株大肠杆菌和其它菌种。结果 12株大肠杆菌O15 7∶H7、1株大肠杆菌O2 6∶H11和 1株大肠杆菌O111∶H8同时检出上述三种基因 ,2株EAEC检出了eaeA基因 ,1株VTEC检出了slt1 2基因 ,其余 43株大肠杆菌和非大肠杆菌未检出上述基因。检测食品中EHEC时 ,从样品增菌培养到整个检测过程结束不超过 8小时 ,方法的检出限≤ 1 6cfu g(ml)。检测的 12 6份食品样品中 ,3份检出了EHEC(包括牛肉、猪肉和生菜各 1份 )。实验结果表明该法是一种特异性强、敏感性高、省时、省力的EHEC检测方法。     

人感染2型猪链球菌快速多重PCR检测方法的建立

目的：用多重PCR从临床标本中同时检测猪链2型特异性及5个毒力相关基因，建立SS2实验室快速诊断及应急检测的核酸鉴定方法。方法：根据已报告的引物序列设计并合成8对引物（含1对内对照引物），经过PCR反应条件的优化与组合，采用同一PCR反应条件与循环程序，直接从临床标本或培养物中同时一次性扩增属特异性（tuf）、种特异性（16S rRNA）、荚膜多糖（cps2J）、溶菌酶释放蛋白（mrp）、细胞外蛋白因子（ef）、溶血素（sly）和甘油醛-3-磷酸脱氢酶（gapdh）等基因；并对方法的特异性和敏感性进行评估。结果：运用所建立的方法可直接从临床疑似猪链感染患者的脑脊液、血液、双相培养液和血培养物中一次性扩增出上述8对引物的目的基因，并经基因序列分析、细菌分离培养和生化鉴定进一步证实。其敏感性为78cfu（克隆形成单位）。结论：所建立的方法具有敏感、特异、快速、简便的特点，可应用于SS2感染应急检测、流行病学监测和实验室快速诊断。     

多重聚合酶链反应技术诊断疟疾及混合感染的研究

目的建立一种特异、敏感、简便的疟疾聚合酶链反应（PCR）快速诊断方法。方法针对疟原虫SSU rRNA基因序列设计3条分别具有属、种特异性的引物,通过多重PCR反应扩增间日疟原虫和恶性疟原虫不同大小的DNA片段。结果 19份恶性疟原虫血样均扩增出长度为400 bp的特定基因片段,16份间日疟原虫扩增出长度为300 bp的特定基因片段,20份健康人群对照血样经PCR扩增均为阴性。结论该多重PCR检测系统具有高效、敏感、特异、稳定、简便等特点,适宜于大批量样品同时检测,对疟疾的快速诊断、鉴别混合感染有较高的应用价值。     

Development and application of a multiplex TaqMan® real-time qPCR assay for the simultaneous detection of Anaplasma marginale and Theileria annulata and molecular characterization of Anaplasma marginale from cattle in Western Cuba.

Anaplasmosis and theileriosis are considered the most important tick-borne diseases for livestock production worldwide, causing significant economic losses in tropical and subtropical regions. The present study was aimed to develop a multiplex TaqMan® qPCR assay to simultaneously detect Anaplasma marginale and Theileria annulata and to applied it to investigate naturally infected cattle in Cuba. The assay was highly specific, sensible, and efficient; it was more sensitive than a well-established nested PCR and detected 1 DNA copy of each target. Consistent repeatability and reproducibility within and between multiplex qPCR runs was shown. A total of 223 blood samples collected in western Cuba were analyzed for haemoparasites infection in cattle. The multiplex qPCR assay detected A. marginale in 213 samples (95.5%; CI: 95%; 91.9%–97.5%), but all samples were negative for T. annulata. Additionally, the genetic diversity of A. marginale was assessed using 16S rRNA, MSP1a and MSP4 nucleotide and protein sequences. The MSP1a tandem repeats ranged from three to five, and twelve different MSP1a tandem repeats of A. marginale were found, which presented genotypes C, E, and G in the 5ʹUTR microsatellite region. Phylogenetic analysis using the msp4 gene showed that Cuban strains were closely related to others previously reported in Mexico, Brazil and Asian countries. The multiplex qPCR described here proved to be a rapid, specific and cost-effective mean for the simultaneous detection of A. marginale and T. annulata. Further epidemiological studies using this assay will improve the surveillance of the associated diseases in regions where they are endemic.     

Protective role of dietary N-acetylcysteine on the oxidative stress induced by cylindrospermopsin in tilapia (Oreochromis niloticus)

Cylindrospermopsin (CYN) is a toxin produced by various cyanobacteria species. Fish can be exposed to this cyanotoxin in their natural environments and in aquaculture ponds, and toxic effects can be derived. The present study investigated the effects of dietary N-acetylcysteine (NAC) on the oxidative stress induced by pure CYN and CYN from lyophilized cells of Aphanizomenon ovalisporum in tilapia (Oreochromis niloticus). Fish were pretreated with 0, 22, and 45 mg NAC/fish/d for a week, and on day seven, they received a single dose of 200 μg/kg CYN and were killed after 24 h. Oxidative biomarkers evaluated included lipid peroxidation, protein oxidation, glutathione (GSH)/oxidized glutathione (GSSG) ratio, activity of the enzyme γ-glutamylcysteine synthetase, and activity and gene expression of glutathione-S-transferase and glutathione peroxidase. Results showed that CYN induced oxidative stress as evidenced by the increase of lipid peroxidation and protein oxidation, the decrease in GSH/GSSG, and the alteration of the enzymatic activities assayed. Moreover, exposure to cyanobacterial cells containing CYN induced higher toxic effects in comparison to pure CYN. N-acetylcysteine supplementation was effective at reducing the toxicity induced by CYN, particularly at the highest dose employed, with a recovery of some of the biomarkers assayed to basal levels. Therefore, NAC can be considered a useful chemoprotectant that reduces hepatic and renal oxidative stress in the prophylaxis and treatment of CYN-related intoxication in fish.     

Detection of pathogenic Yersinia enterocolitica using the multiplex polymerase chain reaction.

A multiplex polymerase chain reaction (PCR) was developed to detect the presence of the ail, yst, and virF genes of Yersinia enterocolitica simultaneously, quickly and accurately. The amplified fragment sizes were 356 base-pairs (bp) for the ail gene, 134 bp for the yst gene, and 231 bp for the virF gene. The specificity of the amplified products was confirmed by hybridization with digoxigenin-labelled oligonucleotide probes. Amplification was successful whether the template was derived from a single colony of bacteria, aliquots of boiled bacterial suspensions, from DNA extracted from pure or mixed cultures or from stool specimens. Amplification of the virF gene was also achieved from strains of Y. pseudotuberculosis carrying the 70 kb plasmid but not with preparations from other related Yersinia species or from other members of the family Enterobacteriaceae. The detection limit we established was 5-10 colony forming units per millilitre (cfu/ml) and 1.0 pg of DNA.     

构建用于相关基因筛选的微囊藻产毒株基因组文库

目的：构建含有微囊藻毒素（MC）表达相关基因的基因组文库,用于分离MC相关基因或鉴别MC表达藻株,方法：使用MC产毒株NIES－90,获取基因组DNA,酶切制备片段,克隆到质粒pUC18中,转化JM109构成基因组文库,结果：建成容量覆盖蓝绿藻基因组10倍以上,插入片段介于200－700bp的NIES－90基因组文库,其中获得至少一段序列具有NIES－90特异性,可能为MC相关基因,结论：构建文库成功,可用于后续MC特异性基因研究。     

产志贺毒素大肠杆菌多重PCR与Vero细胞毒实验对比研究

目的：通过对比研究建立一种具有高特异性，敏感性的检测产志贺毒素大肠杆菌（STEC）的实验方法。方法：应用多重PCR和Vero细胞毒实验方法，对比检测从疫区分离的142株大肠杆菌菌株。结果：60株多重PCR stx2或stx1阳性大肠杆菌Vero细胞毒试验均阳性，82株不含有stx1具有高度的特异性和敏感性，可作为鉴定大肠杆菌是否为STEC的首选方法。     

致病性猪链球菌主要毒力因子基因多重PCR检测

目的建立多重PCR体系．实现猪链球菌毒力相关因子基因cps、mrp、epf，（epf^＊）和sly的同步检测。方法根据上述毒力因子基因核苷酸序列，设计和合成4对特异性引物，通过体系和条件优化，建立多重PCR检测方法，并对72株种属背景明确的实验菌株（其中猪链球菌48株、阴性对照株24株）及49株猪临床分离的链球菌样本进行检测分析。结果48株猪链球菌中，cps2检出率为33．3％（16／48）、mrp检出率为29．2％（14／48）、epf检出率为25％（12／48）、epf^＊检出率为6．3％（3／48）、sly检出率为54．2％（26／48），上述检测结果与菌株的毒力因子背景情况完全相符；24株阴性对照和49株猪临床分离样本毒力因子检测结果均为阴性。结论多重PCR可用于猪链球菌毒力相关因子CPS2、MRP、EF、Sly的基因检测，特异性和敏感性好，为该病快速诊断和分子流行病学调查提供了新的技术手段。     

多重荧光逆转录PCR同时检测肠道病毒71型和柯萨奇病毒A16型

目的建立多重荧光逆转录PCR（RT-PCR）同时检测肠道病毒71型和柯萨奇病毒A16型的方法。方法在肠道病毒71型和柯萨奇病毒A16型VP1基因的保守区序列分别设计特异性引物和Taqman探针,建立优化多重荧光RT-PCR反应体系,评价所建多重荧光RT-PCR反应体系的特异性、敏感性和稳定性,并应用于临床样品检测。结果该方法对肠道病毒71型和柯萨奇病毒A16型检测具有高度特异性,检出限分别为0.1 TCID50和1 TCID50,具有较好的稳定性,可直接应用于临床样品的检测。结论本研究建立的多重荧光RT-PCR可以同时准确检测肠道病毒71型和柯萨奇病毒A16型,灵敏度高,稳定性好,是一种快速检测肠道病毒71型和柯萨奇病毒A16型的新方法。     

耐甲氧西林金黄色葡萄球菌SCCmec分型与耐药性研究

目的研究临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)耐药性,检测MRSA葡萄球菌染色体mec盒(SCCmec)基因型,并进行杀白细胞素(PVL)毒力基因检测。方法采用标准平皿两倍稀释法测定250株MRSA对多种抗菌药物最低抑菌浓度(MIC),采用多重PCR方法对MRSA进行SCCmec基因分型,单一PCR方法对MRSA菌株进行PVL毒力基因检测。结果 250株MRSA经多重PCR方法检测SCCmec基因型,SCCmecⅡ-dcs型菌株30株,占12.0%,Ⅱ型的亚型1株,占0.4%,Ⅲ型62株,占24.8%,含有342 bp(dcs)额外扩增条带的Ⅲ型菌株141株,占56.4%,Ⅳ型7株,占2.8%,Ⅳa型1株,占0.4%,Ⅴ型1株,占0.4%,7株细菌未能分型,占2.8%,未发现Ⅰ型;单一PCR方法获得PVL呈阳性的菌株共2株,占临床分离MRSA的0.8%;各基因型对多种抗菌药物呈现不同程度的耐药。结论临床分离的MRSA以SCCmecⅢ型为主;其次为SCCmecⅡ型;有少量SCCmecⅣ型,少数菌PVL毒力基因阳性。     

常见7种食源性致病菌xMAP液相芯片快速筛查方法的建立及应用

目的采用xMAP液相悬浮芯片检测方法,建立一管同时检测金黄色葡萄球菌、沙门菌、副溶血弧菌、单增李斯特菌、大肠杆菌O157∶H7、创伤弧菌和空肠弯曲菌的快速筛查方法。方法根据GenBank公布的金黄色葡萄球菌肠毒素nuc基因、沙门菌侵袭性基因ssaR、副溶血弧菌通用基因toxR、单增李斯特菌的hlyA基因、大肠杆菌O157∶H7的rfbE基因、创伤弧菌的vvh基因和空肠弯曲菌的gyrA基因,设计特异性引物和探针,利用上游引物和生物素标记的下游引物对7个靶序列进行不对称实时PCR扩增,7重实时PCR扩增产物和制备的7种偶联探针的微球在同一体系中进行杂交,最后利用藻红蛋白和生物素的亲和作用报告荧光,从而建立7种食源性致病菌的xMAP液相悬浮芯片检测法。结果 xMAP液相悬浮芯片体系检测140株菌株,均出现特异性荧光中值信号,7种食源性致病菌检测互不干扰。DNA和菌液检出限分别为1～100ng和105～108cfu/ml对56份各类食品标本进行检测,检出金黄色葡萄球菌2份、沙门菌4份、副溶血弧菌7份、单增李斯特菌1份、创伤弧菌3份,未检出大肠杆菌O157∶H7和空肠弯曲菌,此结果与传统方法分离结果相一致。结论xMAP液相悬浮芯片技术从样品处理到检测结果需3.5h左右,该方法可应用于食品安全风险监测中食源性致病菌的快速筛查和食源性致病菌的分型鉴定。     

三种食源性致病菌多重PCR检测技术建立及应用研究

目的建立多重PCR方法同时检测水产品中沙门菌、副溶血性弧菌和单核细胞增生性李斯特菌。方法分别以沙门菌invA基因、副溶血性弧菌toxR基因和单核细胞增生性李斯特菌iap基因为靶基因,建立并优化了同时检测水产品中这3种致病菌的多重PCR体系,扩增产物分别为495bp(invA)、368bp(toxR)和660bp(iap)。结果建立的多重PCR方法可以简便、快速、灵敏地实现水产品中沙门菌、副溶血性弧菌和单核细胞增生性李斯特菌的同时检测,人工污染水产品检测限为10cfu/ml。结论为无公害水产品食源性致病菌的快速检测提供了理想手段,有良好的应用前景。     

Survey of ground beef for the detection of Mycobacterium avium paratuberculosis

Mycobacterium avium paratuberculosis (MAP) is thought to be associated with Crohn's disease in humans. Since Johne's disease affects dairy and beef cattle, meat may be a possible route of transmission of MAP to humans. In this study, we compared a rapid multiplex real time PCR assay and conventional culture to detect MAP in ground beef. The real time PCR assay amplifies both an internal sequence of the IS900 gene and an internal control targeting the ruminant-specific mt-cyt-b gene, in order to control for any false negative results. The sensitivity of this multiplex real time PCR assay on ground beef is 10(1) CFU/g and the sensitivity of conventional culture at 10(3) CFU/g. Furthermore, we conducted a survey of 200 retail ground beef samples using this system and did not detect the presence of MAP.     

多重PCR法检测外周血单个核细胞中的HBVDNA与HBVcccDNA

目的建立多重聚合酶链反应法(Multiplex Polymerase chain reaction，M—PCR)，揭示慢性乙肝患者外周血单个核细胞(PBMC)中HBVDNA的存在状况。方法采用一种把一套扩增乙肝病毒基因组DNA(HBV genome DNA)的引物和一套特异性扩增乙肝病毒共价闭合环状DNA(HBVcccDNA)的引物掺入到一个体系中的PCR法，检测PBMC中的HBVDNA核酸分子。结果PCR法可使处于同一PBMC中的总HBVDNA和HBVcccDNA同时分别良好的扩增出来；30例慢性乙肝患者的PBMC中，总HBVDNA与HBVcccDNA同耐检出者23例，检出率76．6％；检出HBVcccDNA者占检出总HBVDNA者的82．1％。结论PBMC中的HBVDNA部分参与复制。成功的建立了能同时检测HBV基因组DNA与HBVcccDNA的M—PCR方法。     

PCR和毛细管电泳技术检测沙门氏菌等5种病原菌的方法研究

目的采用多重PCR技术检测结合毛细管电泳成像技术建立快速检测沙门氏菌、志贺氏菌、副溶血性弧菌金黄色葡萄球菌和大肠杆菌O157的方法。方法根据沙门氏菌hilA基因、志贺氏菌ipaH基因、副溶血性弧菌TDH基因、金黄色葡萄球菌的pSa-442 Sau3AI fragment基因及大肠杆菌O157的rfbE基因设计异性特PCR引物,被检样品经4 h振荡培养后金属浴裂解制备DNA模板,使用全自动毛细管电泳核酸检测系统分析PCR扩增产物。结果在580 bp、423bp、257 bp、245 bp和194 bp处分别出现预期的特异性DNA条带,且无非特异扩增条带出现。敏感性试验显示在模拟标本中的检测灵敏度,沙门氏菌为101-2cfu/ml、志贺氏菌为101cfu/ml、副溶血性弧菌为102cfu/ml、金黄色葡萄球菌为102cfu/ml、大肠杆菌O157为101cfu/ml。结论该方法操作方便、特异性和灵敏度高、分辨率高,可同时完成5种病原菌的检测,在公共卫生突发事件中具有实用价值。     

鉴别脑膜炎奈瑟菌A、B、C、Y、W135群的多重聚合酶链反应诊断方法

目的建立一种能鉴别脑膜炎奈瑟菌（Nm）A、B、C、Y、W1355个血清群的多重聚合酶链反应（PCR）方法.方法首先PCR扩增Nm crgA基因,确定Nm感染;再通过多重PCR扩增荚膜表达基因orf-2和siaD基因,根据特异条带区分不同群Nm.结果多重PCR检测61株Nm与4株非Nm,能准确地鉴定并可将Nm分成5个血清群;检测4例流行性脑脊髓膜炎患者的脑脊液,2例出现A群400 bp的特异条带,而细菌培养和胶乳凝集方法检测均为阴性;检测18份流行性乙型脑炎患者标本,与胶乳凝集试验结果一致.结论多重PCR诊断方法能正确鉴别不同群Nm,对流行性脑脊髓膜炎的临床诊断与流行病学调查有重要意义.