Confusing finding of quantitative fluorescent polymerase chain reaction analysis in invasive prenatal genetic diagnosis:A case report

BACKGROUND Quantitative fluorescent polymerase chain reaction(QF-PCR)is a rapid prenatal diagnostic method for abnormalities on chromosomes 21,18,and 13 and sex chromosomal aneuploidy.However,the value of QF-PCR in diagnosing chromosomal structural abnormalities is limited.In this article,we report a confusing QF-PCR finding in a pregnant woman who underwent amniocentesis.CASE SUMMARY The short tandem repeat marker AMXY(Xp22.2/Yp11.2)located on the sex chromosome exhibited a trisomic biallelic pattern,indicating that the karyotype of the fetus might be 47,XYY.Chromosome analysis performed on cultured amniocytes showed a normal male karyotype of the fetus.Copy number variation sequencing confirmed a 500 kb duplication at Yp11.2-Yp11.2(chrY:6610001_7110000)and a 250 kb duplication at Yp11.2-Yp11.2(chrY:7110001_7360000).CONCLUSION In conclusion,the comprehensive application of different methods could achieve a higher detection rate and accuracy for the prenatal diagnosis of chromosomal disorders through chromosomal testing.

Primary application of a real-time quantitative polymerase chain reaction for the detection of human breast cancer related novel gene-Metadherin expression

Objective:The aim of this study was to detect the expression level of Metadherin (MTDH) in peripheral blood of the breast cancer patients by real-time fluorescence quantitative polymerase chain reaction (PCR),and to explore the relationship between expression of Metadherin gene in the patients peripheral blood and the clinic-pathological features in breast cancer. Methods:Real-time fluorescence quantitative polymerase chain reaction was employed to determine the expression level of Metadherin gene in 80 peripheral blood samples of breast cancer patients and healthy donors. Results:The expression of Metadherin gene in breast cancer patients peripheral blood were positive,in which 34 breast cancer patients were highly expressed,accounting for 55.7%,while the expression of Metadherin gene in normal females peripheral blood were negative,there was statistical significance (Ratio = 2.02±0.81,P < 0.05); Ratio of the Metadherin expression in breast cancer patients peripheral blood and the glyceraldehyde-3-phosphate dehydrogenase expression was 1.15 ± 0.36. REST software analysis showed that the expression of Metadherin gene was significantly up-regulated in breast cancer. Conclusion:The SYBR Green I quantitative real-time polymerase chain reaction method can successfully detect the expression level of Metadherin gene. Expression level of Metadherin gene in breast cancer patients peripheral blood is closely related to survival,and it maybe involved in the development of breast cancer and used as an indicator of prognosis.

Real-time Fluorescence PCR Method for Detection of Burkholderia glumae from Rice

Burkholderia glumae causing seedling rot and grain rot of rice was listed as a plant quarantine disease of China in 2007. It＇s quite necessary to set up effective detection methods for the pathogen to manage further dispersal of this disease. The present study combined the real-time PCR method with classical PCR to increase the detecting efficiency, and to develop an accurate, rapid and sensitive method to detect the pathogen in the seed quarantine for effective management of the disease. The results showed that all the tested strains of B. glumae produced about 139 bp specific fragments by the real-time PCR and the general PCR methods, while others showed negative PCR result. The bacteria could be detected at the concentrations of 1×10^4 CFU/mL by general PCR method and at the concentrations below 100 CFU/mL by real-time fluorescence PCR method. B. glumae could be detected when the inoculated and healthy seeds were mixed with a proportion of 1：100.

Comparison of Abbott and Da-an real-time PCR for quantitating serum HBV DNA

AIM: To compare the performance of the Da-an real-time hepatitis B virus (HBV) DNA assay and Abbott RealTime HBV assay.

Establishment of a new quantitative detection approach to adefovir-resistant HBV and its clinical application

AIM:To establish the more feasible and sensitive assessment approach to the detection of adefovir (ADV) resistance-associated hepatitis B virus (HBV) quasispecies.METHODS: Based on the characteristics of rtA181V/T and rtN236T mutations, a new approach based on real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was established for the detection of ADV-resistant HBV quasispecies, total HBV DNA, rtA181 and rtN236 mutations in blood samples from 32 chronic hepatitis B (CHB) patients with unsatisfactory curative effect on ADV and compared with routine HBV DNA sequencing.RESULTS: Both the sensitivity and specificity of this new detection approach to ADV-resistant HBV quasispecies were 100%, which were much higher than those of direct HBV DNA sequencing. The approach was able to detect 0.1% of mutated strains in a total plasmid population. Among the 32 clinical patients, single rtA181 and rtN236T mutation and double rtA181T and rtN236T mutations were detected in 20 and 8, respectively, while ADV-resistant mutations in 6 (including, rtA181V/T mutation alone in 5 patients) and no associated mutations in 26.CONCLUSION: This new approach is more feasible and efficient to detect ADV-resistant mutants of HBV and ADV-resistant mutations before and during ADV treatment with a specificity of 100% and a sensitivity of 100%.

Micro-droplet Digital Polymerase Chain Reaction and Real-Time Quantitative Polymerase Chain Reaction Technologies Provide Highly Sensitive and Accurate Detection of Zika Virus

The establishment of highly sensitive diagnostic methods is critical in the early diagnosis and control of Zika virus(ZIKV)and in preventing serious neurological complications of ZIKV infection. In this study, we established micro-droplet digital polymerase chain reaction(ddPCR) and real-time quantitative PCR(RT-qPCR) protocols for the detection of ZIKV based on the amplification of the NS5 gene. For the ZIKV standard plasmid, the RT-qPCR results showed that the cycle threshold(Ct) value was linear from 10~1 to 10~8 copy/l L, with a standard curve R^2 of 0.999 and amplification efficiency of 92.203%;however, a concentration as low as 1 copy/l L could not be detected. In comparison with RT-qPCR, the dd PCR method resulted in a linear range of 10~1–10~4 copy/l L and was able to detect concentrations as low as 1 copy/l L. Thus, for detecting ZIKV from clinical samples, RT-qPCR is a better choice for high-concentration samples(above 10~1 copy/l L),while ddPCR has excellent accuracy and sensitivity for low-concentration samples. These results indicate that the ddPCR method should be of considerable use in the early diagnosis, laboratory study, and monitoring of ZIKV.

Quantitative Analysis of ATP Sulfurylase and Selenocysteine Methyltransferase Gene Expression in Different Organs of Tea Plant (<i>Camellia sinensis</i>)

Tea plant (Camellia sinensis) has unique biological features for the study of cellular and molecular mechanisms, an evergreen broad-leaved woody plant which can accumulate selenium in soil abundant of Selenium. Expression of the genes related to Selenium (Se) metabolism is an adaptation to the soil environment for a long period. The purpose of the present study was to explore if there exist differences of expression about these genes in tea plant between growing in Selenium-abundant and normal soil. A quantitative real-time reverse transcription polymerase chain reaction (Q-RT-PCR) assay was done for quantification of ATP sulfurylase (APS) and selenocysteine methyltransferase (SMT) mRNA normalized to Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene in tea plant. Young leaves, mature leaves and tender roots from tea plants growing in soil abundant of Selenium were respectively obtained from Shitai County, Anhui Province, and also the relevant materials of the selenium un-enriched tea plant planted at agricultural garden of Ahui Agriculture University were taken as control for real-time PCR analysis. The results showed that APS1, APS2 and SMT expression levels for either young or mature leaves in selenium-enriched tea plant were lower than that in ordinary (selenium un-enriched) tea plant. In contrast, the APS1, APS2 and SMT expression level of roots in selenium-enriched tea plant were all higher than that in ordinary tea plant. APS1 gene expression level of roots in selenium-enriched tea plant was about 1.6 times higher than that in the ordinary tea plant, APS2 gene expression level was about 4.8-fold higher than that in the ordinary tea plant, SMT gene expression level was about 3.3 times higher than that in the ordinary tea plant. Among various tissues of selenium-enriched tea plant, APS1 gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the lowest among them;APS2 gene relative expression level of young leaves was similar to or slightly higher than the roots, and the one of mature leaves was the lowest among them;SMT gene relative expression level of young leaves was similar to or slightly higher than mature leaves, and the one of roots was the highest among them. Our results suggest that there existed correlation between selenium and expression levels of these genes.

Quantitative analysis of a panel of gene expression in prostate cancer——with emphasis on NPY expression analysis

Objective： To investigate molecular alterations associating with prostate carcinoma progression and potentially provide information toward more accurate prognosis/diagnosis. Methods： A set of laser captured microdissected （LCM） specimens from 300 prostate cancer （PCa） patients undergoing radical prostatectomy （RP） were defined. Ten patients representing ＂aggressive＂ PCa, and 10 representing ＂non-aggressive＂ PCa were selected based on prostate-specific antigen （PSA） recurrence, Gleason score, pathological stage and tumor cell differentiation, with matched patient age and race between the two groups. Normal and neoplastic prostate epithelial cells were collected with LCM from frozen tissue slides obtained from the RP specimens. The expressions of a panel of genes, including NPY, PTEN, AR, AMACR, DD3, and GSTP1, were measured by quantitative real-time RT-PCR （TaqMan）, and correlation was analyzed with clinicopathological features. Results： The expressions of AMACR and DD3 were consistently up-regulated in cancer cells compared to benign prostate epithelial cells in all PCa patients, whereas GSTP1 expression was down regulated in each patient. NPY, PTEN and AR exhibited a striking difference in their expression patterns between aggressive and non-aggressive PCas （P=0.0203, 0.0284, and 0.0378, respectively, Wilcoxon rank sum test）. The lower expression of NPY showed association with ＂aggressive＂ PCas based on a larger PCa patient cohort analysis （P=0.0037, univariate generalized linear model （GLM） analysis）. Conclusion： Despite widely noted heterogeneous nature of PCa, gene expression alterations ofAM,4CR, DD3, and GSTP1 in LCM-derived PCa epithelial cells suggest for common underlying mechanisms in the initiation of PCa. Lower NPY expression level is significantly associated with more aggressive clinical behavior of PCa; PTEN and AR may have potential in defining PCa with aggressive clinical behavior. Studies along these lines have potential to define PCa-associated gene expression alterations and likely co-regulation of genes/pathways critical in the biology of PCa onset/progression.

Rapid prenatal diagnosis of trisomy 21 by fluorescent quantitative multiplex polymerase chain reaction

Trisomy 21, also named Down syndrome was the most frequent autosomal aneuploidy and the most common cause of mental retardation. Fifty percent patients had congenital heart malformation. Every 20 minutes one case of trisomy 21 was born, and the incidence rate was 1 in 600 to 800 newborns in China.1 In two thirds of cases with trisomy 21, there was a spontaneous abortion, so the actual incidence was higher than that obtained postnatally.

Reference genes for quantitative RT-PCR data in gastric tissues and cell lines

AIM:To evaluate the suitability of reference genes in gastric tissue samples and cell lines.METHODS:The suitability of genes ACTB,B2M,GAPDH,RPL29,and 18S rRNA was assessed in21 matched pairs of neoplastic and adjacent nonneoplastic gastric tissues from patients with gastric adenocarcinoma,27 normal gastric tissues from patients without cancer,and 4 cell lines using reverse transcription quantitative real-time polymerase chain reaction(RT-qPCR).The ranking of the best single and combination of reference genes was determined by NormFinder,geNorm,BestKeeper,and DataAssist.In addition,GenEx software was used to determine the optimal number of reference genes.To validate the results,the mRNA expression of a target gene,DNMT1,was quantified using the different reference gene combinations suggested by the various software packages for normalization.RESULTS:ACTB was the best reference gene for all gastric tissues,cell lines and all gastric tissues plus cell lines.GAPDH+B2M or ACTB+B2M was the best combination of reference genes for all the gastric tissues.On the other hand,ACTB+B2M was the best combination for all the cell lines tested and was also the best combination for analyses involving all the gastric tissues plus cell lines.According to the GenEx software,2 or 3 genes were the optimal number of references genes for all the gastric tissues.The relative quantification of DNMT1 showed similar patterns when normalized by each combination of reference genes.The level of expression of DNMT1 in neoplastic,adjacent non-neoplastic and normal gastric tissues did not differ when these samples were normalized using GAPDH+B2M(P=0.32),ACTB+B2M(P=0.61),or GAPDH+B2M+ACTB(P=0.44).CONCLUSION:GAPDH+B2M or ACTB+B2M is the best combination of reference gene for all the gastric tissues,and ACTB+B2M is the best combination for the cell lines tested.

Prenatal diagnosis of Down syndrome using cell-free fetal DNA in amniotic fluid by quantitative fluorescent polymersase chain reaction

Backgroud Amniotic fluid （AF） supernatant contains cell-free fetal DNA （cffDNA） fragments.This study attempted to take advantage of cffDNA as a new material for prenatal diagnosis,which could be combined with simple quantitative fluorescent polymerase chain reaction （QF-PCR） to provide an ancillary method for the prenatal diagnosis of trisomy 21 syndrome.Methods AF supernatant samples were obtained from 27 women carrying euploid fetuses and 28 women carrying aneuploid fetuses with known cytogenetic karyotypes.Peripheral blood samples of the parents were collected at the same time.Short tandem repeat （STR） fragments on chromosome 21 were amplified by QF-PCR.Fetal condition and the parental source of the extra chromosome could be determined by the STR peaks.Results The sensitivity of the assay for the aneuploid was 93％ （26/28; confidence interval,CI：77％-98％） and the specificity was 100％ （26/26; CI：88％-100％）.The determination rate of the origin of the extra chromosome was 69％.The sensitivity and the specificity of the assay in the euploid were 100％ （27/27）.Conclusions Trisomy 21 can be prenatally diagnosed by the QF-PCR method in AF supernatant.This karyotype analysis method greatly reduces the requirement for the specimen size.It will be a benefit for early amniocentesis and could avoid pregnancy complications.The method may become an ancillary method for prenatal diagnosis of trisomy 21.

饮食习惯与肥胖患儿性早熟的相关性分析

目的探讨饮食习惯与肥胖患儿性早熟的相关性分析。方法选取苏州市吴中人民医院2019年3月至2022年3月期间收治的72例性早熟肥胖患儿作为观察组,另选取同期体检的健康肥胖儿童71例作为常规组。采用实时-逆转录荧光定量聚合酶链反应(RT-qPCR)检测两组外周血miR-125b水平,分析患儿饮食习惯。通过比较两组肥胖儿童的外周血miR-125b、饮食习惯,采用Logistic回归分析法分析外周血miR-125b、饮食习惯与肥胖患儿性早熟的关系。结果观察组外周血miR-125b表达水平高于常规组,差异有统计学意义(P<0.05)。观察组饮食没规律、荤多素少、高添加剂食品占比均高于常规组,差异有统计学意义(P<0.05)。观察组女性患儿、不良饮食习惯占比高于常规组,且经多因素分析显示外周血miR-125b表达水平、女性、不良饮食习惯是肥胖患儿性早熟的独立危险因素,差异有统计学意义(P<0.05)。结论肥胖患儿性早熟外周血miR-125b表达水平高于健康肥胖儿童,不良饮食习惯高于健康肥胖儿童,外周血miR-125b表达水平偏高、不良饮食习惯偏低均为肥胖患儿性早熟的影响因素。

血清lncRNA T342620联合AFP对肝癌的诊断价值

目的探究肝癌患者血清长链非编码RNA(lncRNA)T342620的表达水平,及其单独或联合甲胎蛋白(AFP)诊断肝癌的临床应用价值。方法采用病例对照研究,收集2021年4月至2023年5月在中国人民解放军南部战区总医院治疗的69例原发性肝癌患者(肝癌组)、32例乙型肝炎患者(乙肝组)、20例肝硬化患者(肝硬化组)、30例原发性肝癌经导管肝动脉化疗栓塞术(TACE)术后患者(肝癌术后组)和同期进行体检的50例健康者(健康体检组)的血清,提取血清总RNA,采用实时荧光定量PCR技术,检测血清中lncRNA T342620的相对表达量;结合患者临床诊疗资料,分析其表达水平与病理特征和血清学相关指标的相关性;运用受试者工作特征(ROC)曲线分析lncRNA T342620单独及联合AFP对肝癌诊断的特异度和灵敏度。根据ROC曲线下面积(AUC)判断诊断效能,评估其在肝癌诊断中的应用价值。各组间比较采用χ^(2)检验,相关性分析采用Spearman法。结果lncRNA T342620在肝癌组和肝癌术后组血清表达水平较健康体检组、乙肝组、肝硬化组高,差异均具有统计学意义(P<0.001);临床病理和血清学相关指标分析显示:肿瘤越大,血清lncRNAT342620表达水平越高,肝癌组血清lncRNA T342620表达水平与白蛋白(ALB)和白球比(A/G)呈负相关(P<0.05),与α-L-岩藻糖苷酶(AFU)和HBV-DNA呈正相关(P<0.05),肝癌术后组患者血清lncRNA T342620表达水平与总胆汁酸(TBA)呈正相关(P<0.05);ROC曲线分析显示:血清lncRNA T342620用于区别肝癌患者与健康者、乙肝和肝硬化患者时,其灵敏度和特异度分别为55.1%和94.1%,具有较好的诊断价值;和AFP联合检测时,灵敏度和特异度分别为91.3%和91.2%,其灵敏度高于各单项指标诊断的灵敏度,且联合检测诊断效能最高,AUC为0.954,与AFP和lncRNA-T342620单独检测的AUC(0.906、0.758)比较,差异有统计学意义(P<0.05)。结论血清lncRNA T342620有可能成为肝癌辅助诊断的新型血清分子标志物。

Influences of bracket bonding on mutans streptococcus in plaque detected by real time fluorescence-quantitative polymerase chain reaction

Background Enamel demineralization occurs frequently during orthodontic treatment. In this study, we evaluated the changes of the density of mutans streptococcus （MS） in plaque after bracket bonding and using fluoride adhesive on maxillary incisors by real time fluorescence-quantitative polymerase chain reaction （RT-FQ PCR）.Methods The study was designed as a self-paired test. Brackets were bonded with fluoride adhesive on the left side, while non-fluoride adhesive on the right side for each patient. Plaque samples were taken from the surfaces around the brackets of four maxillary incisors before brackets bonding and after the bonding 4 weeks later. The amount of MS was measured by RT-FQ PCR. The data obtained were analyzed statistically using the SPSS 11.5 version and the alpha level was set at 0. 05 （ 2-tailed）.Results The amount of MS in plaque increased significantly after bracket bonding （ P 〈 0.01 ）, whereas no significant differences were observed among four maxillary incisors both before and after brackets bonding （P 〉 0. 05 ）, and among the incisors using and not using fluoride adhesive （ P 〉 0. 05 ）.Conclusions The increase of the density of MS in plaque after bracket bonding is one of the etiological factors for enamel demineralization in orthodontic patients. The result of this study did not support what we observed clinically that the incidence of enamel demineralization for lateral incisors was higher than that for central incisors. Using fluoride adhesive for bonding did not affect the amount of MS in plaque in our study. Further study is needed.

鼠李糖乳杆菌HN001菌株水平快速定量方法的建立及应用

目的应用实时荧光定量聚合酶链式反应(real-time fluorescence quantitative polymerase chain reaction,qPCR),建立鼠李糖乳杆菌HN001菌株水平的快速定量检测方法。方法通过比对鼠李糖乳杆菌HN001的近缘菌株的基因组,筛选出鼠李糖乳杆菌HN001菌株水平的特异基因,以菌株水平的特异基因为靶标设计引物及探针,优化反应体系和条件,建立鼠李糖乳杆菌HN001株水平的qPCR检测方法。对方法的特异性、灵敏度、检出限进行验证,并采用已建立的qPCR方法进行模拟添加样品和实际样品的检测。结果所建立的方法特异性强,与近缘菌株无交叉反应,鼠李糖乳杆菌HN001纯培养液检出限为10^(2)CFU/mL,灵敏度可达到650 copies/μL,可在2 h内完成样品检测。对模拟添加样品以及实际样品检测中qPCR和平板计数法结果的对数值进行显著性分析检验,两种方法的测定值结果均无显著性差异(P>0.05)。结论本研究建立的qPCR检测方法可有效应用于益生菌产品中鼠李糖乳杆菌HN001菌株水平定量检测,具有快速、灵敏、准确的特点。

基于连接酶链式反应的EML4-ALK融合基因分型检测

针对棘皮动物微管相关蛋白样4-间变性淋巴瘤激酶(EML4-ALK)融合基因变异体V1、V2、V3a、V3b设计引物、探针,优化连接探针长度及其浓度,建立基于连接酶链式反应的qPCR法检测方案,并对该方案的特异性、检出限、抗干扰性进行验证。结果表明:基于连接酶链式反应的qPCR法能对EML4-ALK融合基因进行有效分型;连接探针长度在30 nt(nucleotide)时检测灵敏度、特异性最高;连接探针终浓度在0.1~1.0 nmol/L较为合适;设计的引物、探针特异性好,只扩增靶RNA,对其他RNA无扩增;对EML4-ALK融合基因变异体V1、V2的检出限为10 copies/μL,变异体V3a、V3b的检出限为100 copies/μL;在EML4-ALK融合基因RNA标准品检测过程中加入100 ng的肺癌样本RNA作为干扰,检测结果未受到明显干扰。

基于微流控芯片技术的创伤弧菌特异性引物的筛选及验证

目的探讨适用于创伤弧菌的特异性引物,通过微流控芯片技术进行一站式检测,为快速检测出病原体奠定基础。方法通过NCBI网站获取靶基因序列,采用MEGA7.0软件对齐后设计出19对引物,BLAST确定引物的特异度,再通过引物性能、灵敏度、快速变温实验筛选适用于微流控的引物,最后对引物的特异度与灵敏度进行评价。结果成功筛选出1对适用于微流控的引物vvhA10,微流控检测结果发现其特异度与灵敏度较高。结论筛选出适用于微流控芯片的引物,用于全自动微流控检测可以满足应急检测或现场快速检测等方面的使用需求。

SYBR GreenⅠ染料-实时荧光定量聚合酶链式反应法检测发酵乳中的霉菌和酵母含量

目的建立一种应用SYBR GreenⅠ染料的实时荧光定量聚合酶链式反应法快速检测发酵乳中的霉菌和酵母菌。方法本研究针对霉菌与酵母菌的保守序列设计引物,确定最优反应体系与反应条件。通过熔解曲线以及非目标菌株的检测验证该方法的特异性;通过菌悬液的梯度稀释检测确定该方法的灵敏度;通过菌悬液与发酵乳样品混合后进行检测,确定该方法的检出限,并得到标准曲线。结果该方法能够特异性的检测发酵乳中的霉菌、酵母菌,无交叉反应。该方法检测霉菌、酵母菌的灵敏度均为10^(2) CFU/mL,并且当菌悬液与发酵乳样品混合后,并没有降低该方法的检出限。在10^(2)~10^(6) CFU/mL浓度范围内,菌液浓度的对数值与循环阈值(cyclethreshold,Ct)具有良好的线性关系,可以在市售样品的检测中通过Ct值计算样品中目标菌的含量,更快的判断发酵乳是否被霉菌、酵母菌污染。结论该方法可用于发酵乳中霉菌和酵母菌的快速检测,为发酵乳的食品安全提供了技术保障。

不同分子检测技术对艾滋病患者合并寄生虫感染在真实世界的应用效果比较

目的对住院艾滋病患者进行合并寄生虫感染的初步检验,比较不同DNA检测技术对艾滋病患者合并寄生虫感染在真实世界的应用效果。方法选择临床诊断为合并弓形虫感染或肺孢子虫感染的16例住院艾滋病患者作为研究对象,以临床诊断为“金标准”进行实验室分子检测。检测方法包括针对不同靶基因的荧光定量聚合酶链反应(qPCR)和环介导等温扩增技术(LAMP);临床样本包括脑脊液、血浆和支气管肺泡灌洗液(BALF);比较采用不同方法和临床样本的检测结果。结果采用Rep-529作为靶基因,LAMP与qPCR诊断艾滋病合并弓形虫感染的总检出率均为53.12%,差异无统计学意义(P>0.05)。对脑脊液样本进行LAMP-529-11和qPCR-529检测的检出率显著高于血浆样本〔90.62%(29/32)比15.62%(5/32),P<0.01〕。采用BALF样本临床诊断合并肺孢子虫肺炎的检出率显著高于血浆样本〔100.00%(32/32)比18.75%(6/32),P<0.01〕。LAMP-18S检测的检出率显著高于LAMP-Cob检测引物组〔65.62%(21/32)比46.87%(15/32),P<0.05〕。LAMP-18S与qPCR-mtSSU的总检出率比较差异无统计学意义〔65.62%(21/32)比53.12%(17/32),P>0.05〕。结论采用Rep-529作为靶基因对艾滋病患者合并弓形虫感染进行检测,qPCR和LAMP方法均可选,建议首选样本为脑脊液;肺孢子虫肺炎检测也可选qPCR和LAMP方法,建议首选样本为BALF。当选择LAMP方法时,建议首选针对18S的引物组。

多重荧光定量聚合酶链反应法检测肉制品中的3种食源性致病菌

目的建立多重荧光定量聚合酶链反应法(quantitative polymerase chain reaction,qPCR)快速检测肉制品中沙门氏菌、单增李斯特菌、大肠杆菌O157:H73种食源性致病菌的方法。方法根据沙门氏菌的invA基因、单增李斯特菌的hemolysin基因、大肠杆菌O157:H7的rfbE基因序列分别设计特异性引物及探针,通过优化反应体系,测定其灵敏度、特异性和重复性,建立了可同时检测上述3种食源性致病菌多重qPCR方法。结果该方法只扩增3种靶细菌,对其他供试菌不扩增;沙门氏菌、单增李斯特菌、大肠杆菌O157:H7的检出限分别为10^(1)、10^(2)、10^(2)拷贝数/μL,并且拥有良好的重复性和特异性。人工污染的猪肉样品经SLE培养基富集8 h后,分别可以检测到初始菌液浓度为1.56×10^(2)CFU/25 g的沙门氏菌,2.13×10^(2)CFU/25 g的单增李斯特菌,2.32×10^(2)CFU/25 g的大肠杆菌O157:H7。结论所建立的多重qPCR灵敏度高、特异性强、重复性好,可同时检测肉制品中沙门氏菌、单增李斯特菌和大肠杆菌O157:H73种食源性致病菌,在提高食品安全和保护人类健康方面有重要意义。