Qvarnstrom Yvonne, Visvesvara Govinda S, Sriram Rama, da Silva Alexandre J
Parasitic Diseases Branch, Division of Parasitic Diseases, Centers for Disease Control and Prevention, 4700 Buford Highway NE, Mail Stop F36, Atlanta, GA 30341-3724.
J Clin Microbiol. 2006 Oct;44(10):3589-95. doi: 10.1128/JCM.00875-06.
Infections caused by Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris occur throughout the world and pose many diagnostic challenges. To date, at least 440 cases of severe central nervous system infections caused by these amebas have been documented worldwide. Rapid and specific identification of these free-living amebas in clinical samples is of crucial importance for efficient case management. We have developed a triplex real-time TaqMan PCR assay that can simultaneously identify Acanthamoeba spp., B. mandrillaris, and N. fowleri in the same PCR vessel. The assay was validated with 22 well-characterized amebic strains harvested from cultures and nine clinical specimens that were previously characterized by in vitro culture and/or immunofluorescence assay. The triplex assay demonstrated high specificity and a rapid test completion time of less than 5 h from the reception of the specimen in the laboratory. This assay was able to detect one single ameba per sample analyzed, as determined with cerebrospinal fluid spiked with diluted cultured amebas. This assay could become useful for fast laboratory diagnostic assessment of amebic infections (caused by free-living amebas) in laboratories with adequate infrastructure to perform real-time PCR testing.
福氏耐格里阿米巴、棘阿米巴属和曼氏巴通体引起的感染在全球范围内均有发生，并带来了诸多诊断挑战。迄今为止，全球已记录了至少440例由这些阿米巴引起的严重中枢神经系统感染病例。在临床样本中快速、特异性地鉴定这些自由生活的阿米巴对于有效的病例管理至关重要。我们开发了一种三重实时TaqMan PCR检测方法，该方法可在同一PCR管中同时鉴定棘阿米巴属、曼氏巴通体和福氏耐格里阿米巴。该检测方法用从培养物中收获的22株特征明确的阿米巴菌株以及9份先前通过体外培养和/或免疫荧光检测进行过特征鉴定的临床标本进行了验证。三重检测方法显示出高特异性，从实验室收到标本起不到5小时即可完成检测。用稀释的培养阿米巴加样的脑脊液检测确定，该检测方法能够检测出每份分析样本中的单个阿米巴。对于具备进行实时PCR检测的适当基础设施的实验室，该检测方法可能有助于对阿米巴感染（由自由生活的阿米巴引起）进行快速实验室诊断评估。
