Talundzic Eldin, Maganga Mussa, Masanja Irene M, Peterson David S, Udhayakumar Venkatachalam, Lucchi Naomi W
Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Malar J. 2014 Jan 27;13:31. doi: 10.1186/1475-2875-13-31.
Accurate diagnosis of malaria infections remains challenging, especially in the identification of submicroscopic infections. New molecular diagnostic tools that are inexpensive, sensitive enough to detect low-level infections and suitable in laboratory settings of resource-limited countries are required for malaria control and elimination programmes. Here the diagnostic potential of a recently developed photo-induced electron transfer fluorogenic primer (PET) real-time polymerase chain reaction (PCR) called PET-PCR was investigated. This study aimed to (i) evaluate the use of this assay as a method for the detection of both Plasmodium falciparum and other Plasmodium species infections in a developing country's diagnostic laboratory; and, (ii) determine the assay's sensitivity and specificity compared to a nested 18S rRNA PCR.
Samples used in this study were obtained from a previous study conducted in the region of Iringa, Tanzania. A total of 303 samples from eight health facilities in Tanzania were utilized for this evaluation. All samples were screened using the multiplex PET-PCR assay designed to detect Plasmodium genus and P. falciparum initially in laboratory in Tanzania and then repeated at a reference laboratory at the CDC in the USA. Microscopy data was available for all the 303 samples. A subset of the samples were tested in a blinded fashion to find the sensitivity and specificity of the PET-PCR compared to the nested 18S rRNA PCR.
Compared to microscopy, the PET-PCR assay was 59% more sensitive in detecting P. falciparum infections. The observed sensitivity and specificity were 100% (95% confidence interval (CI0.95) = 94-100%) and (CI0.95 = 96-100%), respectively, for the PET-PCR assay when compared to nested 18S rRNA PCR. When compared to 18S rRNA PCR, microscopy had a low sensitivity of 40% (CI0.95 = 23-61%) and specificity of 100% (CI0.95 = 96-100%). The PET-PCR results performed in the field laboratory in Tanzania were in 100% concordance with the results obtained at the reference laboratory in the USA.
The PET-PCR is a new molecular diagnostic tool with similar performance characteristics as commonly used PCR methods that is less expensive, easy to use, and amiable to large scale-surveillance studies in developing country settings.
疟疾感染的准确诊断仍然具有挑战性，尤其是在亚显微感染的识别方面。疟疾控制和消除计划需要新的分子诊断工具，这些工具价格低廉、灵敏度足以检测低水平感染且适用于资源有限国家的实验室环境。在此，研究了一种最近开发的名为PET-PCR的光诱导电子转移荧光引物实时聚合酶链反应（PCR）的诊断潜力。本研究旨在：（i）评估该检测方法作为一种在发展中国家诊断实验室中检测恶性疟原虫和其他疟原虫物种感染的方法的实用性；以及（ii）与巢式18S rRNA PCR相比，确定该检测方法的灵敏度和特异性。
本研究中使用的样本取自先前在坦桑尼亚伊林加地区进行的一项研究。总共利用了来自坦桑尼亚八个卫生设施的303个样本进行该评估。所有样本首先在坦桑尼亚的实验室中使用设计用于检测疟原虫属和恶性疟原虫的多重PET-PCR检测方法进行筛查，然后在美国疾病控制与预防中心（CDC）的参考实验室中重复进行。所有303个样本都有显微镜检查数据。以盲法对一部分样本进行检测，以确定PET-PCR与巢式18S rRNA PCR相比的灵敏度和特异性。
与显微镜检查相比，PET-PCR检测方法在检测恶性疟原虫感染方面的灵敏度高59%。与巢式18S rRNA PCR相比，PET-PCR检测方法观察到的灵敏度和特异性分别为100%（95%置信区间（CI0.95）=94-100%）和（CI0.95=96-100%）。与18S rRNA PCR相比，显微镜检查的灵敏度较低，为40%（CI0.95=23-61%），特异性为100%（CI0.95=96-100%）。在坦桑尼亚现场实验室进行的PET-PCR结果与在美国参考实验室获得的结果100%一致。
PET-PCR是一种新的分子诊断工具，其性能特征与常用的PCR方法相似，价格更低、易于使用，并且适合在发展中国家环境中进行大规模监测研究。
