ASPCR检测微量HIV-1 K103N耐药突变方法的建立

目的 建立检测微量HIV-1 K103N耐药突变的等位基因特异扩增实时定量PCR(allele-specific real-time PCR,ASPCR)方法,用于微量K103N耐药突变的检测和分析.方法 首先建立检测K103N耐药突变的ASPCR方法,然后对方法进行验证,最后采用ASPCR方法检测对照样本.构建含K103N突变的质粒作为标准品,然后设计特异性引物用以区分野生型和突变型模板,采用SYBR green法进行实时定量PCR,并绘制标准曲线.分别采用特异性和非特异性引物扩增模板,根据二者Ct(cycle threshold)值结合相应的标准曲线判断是否存在K103N突变及突变比例.对ASPCR检测K103N突变位点的特异性、敏感性、准确性、重复性等进行验证.结果 特异性和非特异性引物扩增等量野生型模板的Ct值之差(△Ct)可达13.56;当突变比例小于0.1%时仍具有良好的准确性;批内变异系数小于0.7,批间变异系数小于1.6;检测灵敏度可达0.01%.检测阴性对照样本的△Ct显著高于临界值,阳性对照样本检测结果均为刚性.结论 ASPCR是一种快速、灵敏、准确的检测HIV-1微量耐药突变的方法,可为临床抗病毒治疗提供理论指导.     

Evaluation of a rapid and completely automated real-time reverse transcriptase PCR assay for diagnosis of enteroviral meningitis

Nucleic acid amplification tests (NAATs) for enterovirus RNA in cerebrospinal fluid (CSF) have emerged as the new gold standard for diagnosis of enteroviral meningitis, and their use can improve the management and decrease the costs for caring for children with enteroviral meningitis. The Xpert EV assay (Cepheid, Sunnyvale, CA) is a rapid, fully automated real-time PCR test for the detection of enterovirus RNA that was approved by the U.S. Food and Drug Administration for in vitro diagnostic use in March 2007. In this multicenter trial we established the clinical performance characteristics of the Xpert EV assay in patients presenting with meningitis symptoms relative to clinical truth. Clinical truth for enteroviral meningitis was defined as clinical evidence of meningitis, the absence of another detectable pathogen in CSF, and detection of enterovirus in CSF either by two reference NAATs or by viral culture. A total of 199 prospectively and 235 retrospectively collected specimens were eligible for inclusion in this study. The overall prevalence of enteroviral meningitis was 26.04%. The Xpert EV assay had a sensitivity of 94.69% (90% confidence interval [CI] = 89.79 to 97.66%), specificity of 100% (90% CI = 99.07 to 100%), positive predictive value of 100%, negative predictive value of 98.17, and an accuracy of 98.62% relative to clinical truth. The Xpert EV assay demonstrated a high degree of accuracy for diagnosis of enteroviral meningitis. The simplicity and on-demand capability of the Xpert EV assay should prove to be a valuable adjunct to the evaluation of suspected meningitis cases.