Rapid detection of haptoglobin gene deletion in alkaline-denatured blood by loop-mediated isothermal amplification reaction

Anhaptoglobinemic patients run the risk of severe anaphylactic transfusion reaction because they produce serum haptoglobin antibodies. Being homozygous for the haptoglobin gene deletion allele (HP(del)) is the only known cause of congenital anhaptoglobinemia, and detection of HP(del) before transfusion is important to prevent anaphylactic shock. In this study, we developed a loop-mediated isothermal amplification (LAMP)-based screening for HP(del). Optimal primer sets and temperature for LAMP were selected for HP(del) and the 5' region of the HP using genomic DNA as a template. Then, the effects of diluent and boiling on LAMP amplification were examined using whole blood as a template. Blood samples diluted 1:100 with 50 mmol/L NaOH without boiling gave optimal results as well as those diluted 1:2 with water followed by boiling. The results from 100 blood samples were fully concordant with those obtained by real-time PCR methods. Detection of the HP(del) allele by LAMP using alkaline-denatured blood samples is rapid, simple, accurate, and cost effective, and is readily applicable in various clinical settings because this method requires only basic instruments. In addition, the simple preparation of blood samples using NaOH saves time and effort for various genetic tests.     

环介导等温扩增技术快速检测结核分枝杆菌核酸

摘要:目的：建立一种快速准确的检测结核分枝杆菌（MTB）核酸的环介导等温扩增（LAMP）方法。 方法：以重复插入序列IS6110为目的基因,设计LAMP引物,特异检测MTB核酸。用本法与痰涂片抗酸染色镜检法、实时荧光PCR法对100例可疑患者痰标本进行对比检查。 结果：LAMP法特异性强,仅扩增MTB复合群核酸;灵敏度高,检测限达100 fg;而实时荧光PCR检测限为1 pg。对100例疑似结核病患者痰液标本检测,涂片抗酸染色法、LAMP法、实时荧光PCR法的阳性率分别为28%、39%和38%。 结论：本研究建立的LAMP方法检测MTB核酸特异性强、灵敏度高、时间短且操作简便,有望成为临床快速检测MTB的新方法。     

基于环介导恒温扩增法快速检测破伤风梭菌

目的 利用环介导恒温扩增技术,设计快速检测破伤风梭菌的方法,以便对破伤风梭菌感染进行快速检测.方法 (1)设计针对破伤风梭菌的环介导恒温扩增检测方法.(2)对破伤风梭菌恒温扩增法进行特异性试验.(3)对破伤风梭菌恒温扩增法进行灵敏度试验.结果 (1)设计出针对破伤风梭菌的恒温扩增检测方法.(2)本恒温扩增检测方法只扩增...     

霍乱弧菌CT毒素环介导等温扩增技术快速检测方法的建立

目的将一种新颖的核酸扩增技术——环介导等温扩增技术(LAMP)应用于霍乱弧菌毒素基因ctxA的快速检测。方法针对霍乱弧菌毒素基因ctxA设计6条特异性引物(两条内引物、两条外引物和两条环引物)进行LAMP扩增,对扩增反应进行优化。并考核方法的敏感性和特异性。结果最佳反应时间为60 min,反应温度为65℃。对8种相关肠道细菌进行LAMP扩增,仅含毒素基因ctxA的霍乱弧菌得到阳性扩增结果,证明引物具有很高的特异性。霍乱弧菌基因组DNA和纯培养物的检测灵敏度分别约为68 fg和42 cfu/ml。对模拟样品进行直接检测,检测限为72 cfu/g。结论该方法检测霍乱弧菌毒素基因ctxA特异性强、灵敏度高,并且操作简便、检测成本低,1 h即可完成,适合基层检验部门使用。     

高灵敏度等温扩增法可视化检测血液中的病毒核酸

目的探讨便携式、可灵敏、快速检测血液标本中病毒核酸的方法。方法以HBV病毒为例,针对其基因组保守序列设计特异性引物,采用环介导等温扩增法(LAMP)对待测HBV标本做核酸目标序列扩增,以高灵敏双链DNA嵌合荧光染料为指示剂,根据荧光信号指示扩增反应产物的有无;将本法与实时荧光PCR法对临床标本做HBV检测的对照分析。结果建立了血液病毒核酸的可视化检测方法,研制出扩增检测一体化仪器;灵敏度达到可在<1 h完成10 cp/管的HBV核酸扩增反应和产物检测。62例实时荧光PCR检测为HBV阳性的临床标本,本法亦都检测为阳性;而从42例实时荧光PCR检测为HBV阴性的临床标本中,本法检出了6例HBV阳性。结论所建立的方法和装置可实现高灵敏度单管快速检测血液病毒核酸,为特殊现场环境中的血液安全性筛查提供了新的手段。     

环介导等温扩增技术快速检测副溶血性弧菌

目的建立一种检测副溶血性弧菌（Vp）快速且特异的环介导等温扩增（LAMP）检测方法。方法针对副溶血性弧菌不耐热溶血素（tlh）基因特异性序列的6个位点设计4条LAMP引物,65℃保温约60min,完成对副溶血性弧菌的扩增,扩增产物经肉眼、SYBR Green Ⅰ染色、电泳和酶切鉴定。利用LAMP和普通PCR方法同时检测1株副溶血性弧菌和12株非副溶血性弧菌来验证LAMP方法的特异性;将副溶血性弧菌菌液作一系列10倍稀释后用LAMP和PCR方法进行检测,比较两者敏感性。结果1株副溶血性弧菌出现LAMP扩增反应：通过肉眼、SYBR Green Ⅰ染色和电泳均能观察到LAMP扩增产物的出现,酶切证实了LAMP产物的特异性;12株非副溶血性弧菌未出现LAMP扩增。LAMP检测tlh基因的特异性和敏感性与普通PCR相同,LAMP检测tlh基因的检测下限为15cfu／mL。结论建立了一种快速、敏感、特异的副溶血性弧菌检测方法,适合日常监测及快速检测的需要。     

环介导等温扩增技术的应用

环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术是针对靶基因的6个区域设计4种特异引物,利用一种链置换型DNA聚合酶(Bst DNA polymerase)在恒温65℃左右保温几十分钟快速进行核酸扩增的方法.由于其具有快速、简便、特异性好、灵敏度高、成本低等优...     

环介导等温扩增技术检测肺结核患者感染铜绿假单胞菌的临床应用研究

目的探讨针对opr L基因设计引物的环介导等温扩增技术(LAMP)对铜绿假单胞菌的诊断价值。方法采用LAMP技术对铜绿假单胞菌标准株的DNA样品进行检测,评价LAMP技术的检测限;同时对阴沟肠杆菌和大肠埃希菌等6种标准菌株进行鉴定,评价该方法的特异性。对106例肺结核患者临床痰标本进行普通细菌培养鉴定,对临床分离株进行LAMP技术检测,评价LAMP技术的临床应用价值。采用χ2检验进行统计学分析。结果本研究中采用的LAMP技术对DNA样品检测限为25 pg/μl。LAMP对铜绿假单胞菌质控菌株的DNA样品检测结果为阳性,6种其他普通菌菌株检测结果为阴性,特异度为100%。对临床分离株检测发现LAMP技术与培养法之间差异有统计学意义(χ2=7.11,P<0.01)。结论靶点opr L基因设计引物的LAMP的敏感度和特异度均较高,方法简单快速,适于临床应用。     

基于单一基因的反转录-环介导等温核酸扩增技术快速检测甲型副伤寒沙门菌

目的建立反转录-环介导等温核酸扩增(RT-LAMP)方法特异检测甲型副伤寒沙门菌。方法针对甲型副伤寒沙门菌特异保守hsdM基因设计引物,通过优化反应条件,建立检测该靶基因的RT-LAMP体系。利用多种血清型沙门菌及非沙门菌菌株DNA评价该方法的特异性及敏感性。同时对甲型副伤寒沙门菌全血模拟标本及粪便模拟标本进行敏感性检测,并利用临床样本进行初步验证。结果等温65℃条件下,30~60 min内完成RTLAMP反应,利用该方法检测130株甲型副伤寒沙门菌均为阳性,其他非甲型副伤寒沙门菌均扩增阴性。对纯菌RNA检测中检测下限为50 pg/反应,约为19 000个拷贝/反应。在以全血模拟样本的检测中,敏感性达80 cfu/ml,略高于PCR检测低限。对粪便模拟标本的检测中,对原始样品检测下限为500 cfu/g;增菌后样品检测下限为0.8 cfu/g,比PCR检测低限高2~10倍。临床样本中甲型副伤寒患者血液标本检测均阳性,而伤寒样本检测均阴性。结论建立了敏感性高、特异性好的检测甲型副伤寒沙门菌的RT-LAMP方法,为甲型副伤寒沙门菌感染的快速诊断提供了简易手段,可试用于甲型副伤寒的早期诊断。     

利用环介导恒温扩增法快速检测溶组织梭菌

目的利用环介导恒温扩增技术,设计快速检测溶组织梭菌的方法,研究其反应特性,以期能应用于气性坏疽临床现场检验。方法通过基因比对与引物设计,设计针对溶组织梭菌的环介导恒温扩增检测(LAMP)方法。检测该LAMP方法对溶组织梭菌及其他干扰菌的扩增情况,对其特异性进行评价。(3)检测该LAMP方法对不同浓度溶组织梭菌的扩增情况,观察其最低检测限,对其灵敏度进行评价。结果设计出针对溶组织梭菌的LAMP检测方法。该LAMP检测方法只针对溶组织梭菌有扩增,对其他干扰菌不扩增,显示出良好的特异性。该LAMP检测方法对溶组织梭菌的最低检测限为1×101CFU/mL,显示其灵敏度较高。结论该试验设计出了针对溶组织梭菌的LAMP检测方法,该LAMP检测方法具有良好的特异性较高的灵敏度,能够用于溶组织梭菌的临床现场检验。     

白念珠菌恒温扩增法的建立及其应用价值

目的 建立一种简单快速检测白念珠菌的环介导等温扩增技术（LAMP），并评价其临床价值。方法 采用Primer Explorer V5软件，针对白念珠菌RPS0基因设计4条引物，对LAMP反应体系和反应条件进行优化，评价检测特异性和最低检测限；收集123例VVC组和42例体检组的女性阴道拭子，平行进行真菌培养、LAMP检测、PCR检测、10%KOH镜检，真菌培养作为VVC诊断参考方法；组间检测方法阳性率的比较采用Pearson 2检验，LAMP、PCR、镜检与培养法的一致性采用Kappa检验，P<0.05为差异有统计学意义；应用ROC曲线分析法评价LAMP、PCR在VVC诊断中的价值。结果 LAMP技术的最适反应温度为61°C，且特异性高，与其他常见菌株无交叉反应，检测下限为103 copies/ul；VVC组和体检组的LAMP、PCR、镜检阳性率有统计学差异（LAMP，2=68.576； PCR，2=64.918；镜检，2=50.076，P<0.01）。LAMP和PCR与培养法有较好的一致性（κ=0.744，κ=0.720），镜检与培养法有较差的一致性（κ=0.533）；LAMP对VVC的诊断敏感性87.62%，特异性88.33%，阳性预测值92.93%，阴性预测值80.30%。LAMP、PCR诊断VVC的曲线下面积分别为0.873、0.888，两者的诊断效能无差异（Z=0.849，P = 0.3956），但LAMP检测时间短于1h。结论 建立了检测白念珠菌的快速可靠、敏感性好、特异性高的LAMP技术。检测时间大大缩短，综合筛查性能优于实验室常规方法，可用于白念珠菌感染的辅助诊断和疗效监控。     

Rapid diagnosis of largemouth bass ranavirus in fish samples using the loop-mediated isothermal amplification method

Largemouth bass ranavirus (LMBV) has been recognized as the causative pathogen responsible for infectious skin ulcerative syndrome in cultured largemouth bass in China. A fast and simple LMBV detection method is urgently needed. Here, a loop-mediated isothermal amplification (LAMP) assay was established for the detection of this virus using primers targeting the major capsid protein gene of LMBV. The amplification conditions were optimized; the assay was specific for the diagnosis of LMBV, as there was no cross-reactivity with other four Iridoviridae viruses (large yellow croaker iridovirus, Singapore grouper iridovirus, tiger frog virus, and soft-shelled turtle iridovirus), grass carp reovirus, white spot syndrome virus, or healthy largemouth bass. The sensitivity of the LAMP assay was found to be 8.55 × 10¹ copies/μL of LMBV DNA, which was 10-fold higher than that of the conventional PCR. Application of the LAMP assay was evaluated using 10 clinical samples, and the results indicated the reliability of the test as a rapid, field diagnostic tool for LMBV detection. Thus, the simplicity and nearly instrument-free LAMP method provides an alternative for rapid and sensitive detection of LMBV and has great potential for early diagnosis of LMBV infection in the farm.     

环介导等温扩增技术快速检测金黄色葡萄球菌

目的 建立环介导等温扩增(LAMP)技术快速检测临床标本中金黄色葡萄球菌(SA)的方法.方法 基于金黄色葡萄球菌femA基因部分序列设计一套(共4条)特异性引物,包括特异性识别靶序列上6个不同区域的两条内引物和两条外引物.通过条件优化,建立检测SA的LAMP方法.用该法检测临床分离的40株SA、12种其他革兰阳性球菌和...     

环介导等温扩增检测弓形虫方法的建立

目的建立环介导等温扩增（LAMP）检测弓形虫DNA的方法。方法以构建的弓形虫B1基因质粒为阳性模板,建立LAMP检测弓形虫的方法,并进行特异性和敏感性评估,在此基础上建立LAMP检测弓形虫的定量体系及通过显色反应直接判断结果的简便方法,最后应用建立的方法对57例孕妇外周血标本进行检测。结果建立的方法仅对弓形虫DNA扩增出特有的梯状条带,酶切结果与预期相符;检测下限为每反应管10拷贝。以重组质粒制作的标准曲线,阳性反应时间与模板浓度有良好的线性关系。57例孕妇标本检测,发现2例阳性。结论本方法特异性强、敏感性高、简便快速且成本低,有望在临床检测中发挥一定的作用。     

Sensitive and rapid detection of Aeromonas caviae in stool samples by loop-mediated isothermal amplification

In this study, a loop-mediated isothermal amplification assay targeting the 16S-23S intergenic spacer regions (internal transcribed spacer) of Aeromonas caviae was developed. Eighteen reference strains and 109 clinical samples were analyzed. The results showed this detection technique is more reliable and convenient compared with common polymerase chain reaction and biochemical culture methods.     

Comparison of nucleic acid sequence-based amplification and loop-mediated isothermal amplification for diagnosis of human African trypanosomiasis

Diagnosis of human African trypanosomiasis (HAT) using molecular tests should ideally achieve high sensitivity without compromising specificity. This study compared 2 simplified tests, nucleic acid sequence-based amplification (NASBA) combined with oligochromatography (OC) and loop-mediated isothermal amplification (LAMP), executed on 181 blood samples from 65 Trypanosoma brucei gambiense HAT patients, 86 controls, and 30 serological suspects from Uganda. Basing on the composite reference standard, the diagnostic sensitivity and specificity of NASBA were 93.9% (95% confidence interval [CI] = 84.9–98.3%) and 100% (95% CI = 94.9–100%), respectively. The same parameters for LAMP were 76.9% (95% CI = 64.8–86.5%) and 100% (95% CI = 91.6–100%), respectively. The level of agreement between LAMP and microscopy was good with a kappa (κ) value of 79.2% (95% CI = 69.4–88.9%), while that of NASBA-OC/microscopy was very good (κ value 94.6%; 95% CI = 89.3–99.8%). The sensitivity of NASBA-OC was significantly higher than that of LAMP (Z = 2.723; P = 0.007). These tests have potential application to HAT surveillance.