Nucleic Acid Diagnostic Device for Quantifying Bacteremi

描述(由申请人提供)：在这种严重的脓毒症病例中，只有34%的血液培养呈阳性结果，抗生素的选择通常基于患者的临床病史。在危及生命的病例中，在获得培养结果之前首先使用广谱抗生素进行治疗，因为在最初的48小时内开始治疗可以显著降低死亡率。IQuum开发了一种试管实验室(Liat(Tm))分析仪，可用于在急诊科患者出现后1小时内检测血流感染。这项技术使受过最低限度培训的医疗从业者能够使用全血作为样本输入进行核酸测试。我们建议建立逆转录聚合酶链式反应(RT-PCR)检测16S核糖体RNA的诊断方法。由于每个细胞含有1,000到10,000个拷贝的rRNA，因此该设备的预期灵敏度将允许检测~3个细胞/10毫升全血的菌血症滴度。我们建议使用Bugs‘n beads(Tm)(Genpoint AS)或凝集素涂层过滤器来制备样品；这是一种基于细菌对细菌具有高亲和力的固相基质的初始吸附的方法。或者，我们将探索核酸特异性捕获细菌rRNA。所有这些样品制备替代品都将使用相同的诊断设备进行测试。我们还建议获得FDA对多重检测的批准，并寻求该设备的CLIA豁免状态。我们建议将最初的510(K)重点放在败血症最常见的原因上：大肠杆菌和金黄色葡萄球菌(都是凝固性阴性菌和金黄色葡萄球菌)，它们占血液感染的60%。一旦该设备获得了510(K)对这一有限使用适应症的批准，我们建议在临床试验期间获得额外数据时，提交缩写为510(K)的文件，以检测额外的细菌(列在工作计划正文中)。

DESCRIPTION (provided by applicant): Positive blood culture results are available in only 34% of such severe sepsis cases and antibiotic selection is usually based on the patient's clinical history. In life threatening cases, treatment is initiated with broad spectrum antibiotics before culture results are obtained because initiating treatment in the first 48 hours can significantly lower mortality rates. IQuum has developed a lab-in-a-tube (Liat(tm)) Analyzer which can be used to detect blood stream infections within 1 hour of patient presentation at an emergency department. This technology enables minimally trained healthcare practitioners to perform a nucleic acid test using whole blood as the sample input. We propose to develop a reverse transcriptase polymerase chain reaction (RT-PCR) diagnostic assay for detecting the 16S ribosomal RNA. Because each cell contains 1,000 to 10,000 copies of rRNA the RT-PCR assay, the expected sensitivity of the device will allow for the detection of bacteremia titers of ~3 cells /10 ml of whole blood. We propose to use BUGS'n BEADS(tm) (Genpoint AS) or lectin coated filters for sample preparation; a method based on an initial adsorption of bacteria to a solid phase matrix with high affinity for bacteria. Alternatively, we will explore nucleic acid specific capture of bacterial rRNA. All of these sample preparation alternatives will be tested using the same diagnostic device. We further propose to obtain FDA approval for a multiplex assay as well as seek CLIA waived status for the device. We propose to file our initial 510(k) focusing on the most common causes of sepsis: Escherichia coli and Staphylococcus sp (both coagulate negative species and S. aureus), which account for ~60% of blood stream infections. Once the device has obtained 510(k) approval for this limited indication of use, we propose to file abbreviated 510(k) for the detection of additional bacteria (listed in the body of the Work Plan) as additional data is acquired during the clinical trial.