Lateral flow assay for detecting colonization by Streptococcus agalactiae

用于检测无乳链球菌定植的侧流测定

• 批准号: 7481800
• 负责人: YING LI
• 金额: $ 20.1万
• 依托单位: BIOHELIX CORPORATION
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7481800
• 关键词: Accounting; Agglutination; Antibiotics; Antibodies; Bathing; Binding; Biological Assay; Biotin; Birth; Buffers; Caring; Carrots - dietary; Centers for Disease Control and Prevention (U.S.); Clinical; Clinical Research; DNA; Detection; Devices; Diagnostic; Disease; Economics; Equilibrium; Fever; Filtration; Fluorescein-5-isothiocyanate; Goals; Haptens; Health Care Costs; Heating; Hour; Human; Incidence; Incubated; Invasive; Knowledge; Laboratories; Lateral; Latex; Latex Particles; Lead; Liquid substance; Localized; Manufacturer Name; Materials Testing; Medical center; Membrane; Meningitis; Methods; Microspheres; Molecular; Morbidity - disease rate; Mothers; Multi-Institutional Clinical Trial; National Institute of Allergy and Infectious Disease; Newborn Infant; Nucleic Acid Amplification Tests; Nucleic Acids; Performance; Perinatal Infection; Phase; Physicians; Plastics; Pneumonia; Polymerase Chain Reaction; Pregnancy; Premature Birth; Premature Rupture Fetal Membranes; Preparation; Process; Public Health; Published Comment; Reaction; Reagent; Recording of previous events; Risk; Risk Factors; Rupture; Sales; Sampling; Score; Screening procedure; Sensitivity and Specificity; Sepsis; Site; Solutions; Specificity; Specimen; Standards of Weights and Measures; Step Tests; Streptavidin; Streptococcal Infections; Streptococcus Group B; Swab; System; Term Birth; Testing; Time; Training; Tube; United States; United States Food and Drug Administration; Universities; Vagina; Water; Week; Woman; antimicrobial; base; cost; design; desire; early onset; helicase; instrumentation; internal control; migration; mortality; neonate; prevent; prophylactic; rapid detection

DESCRIPTION (provided by applicant): Streptococcus agalactiae, a.k.a. group B streptococcus (GBS), is one of the leading causes of morbidity, and mortality among newborns. We propose to develop a molecular assay for GBS using our proprietary helicase dependent amplification (HDA), and a lateral flow strip embedded in a device that encloses the reaction vessel to prevent contamination of the laboratory by amplicons. HDA is similar to the polymerase chain reaction (PCR) in that it uses two primers to exponentially amplify nucleic acids. Like PCR, HDA assays can use a competitive internal control; i.e., a template DNA of known concentration spiked into the raw sample that can be amplified by the same primers as the analyte, but detected separately. Unlike PCR, HDA is entirely isothermal, and thus does not require costly thermocyclers. In fact we routinely use water baths to perform assays. The objectives for Phase I are to: 1) Validate the sensitivity and specificity of the assay with a panel of DNA samples from near neighbor strains, as well as strains commonly found in the sampling sites. 2) Evaluate the performance of the filtration sample preparation method proposed in the body with clinical specimens from Dr. Gary Procop, University of Miami Medical Center (UMMC). 3) Develop a clinical plan & a pre-IDE for review by the Food and Drug Administration (FDA) for a multi-site clinical study to seek regulatory clearance for sale of the assay for human diagnostics. The milestone for this Phase I is to deliver a pre-IDE to FDA. Comments from FDA will be used to design a clinical study during Phase II. We believe our proposed assay system can obtained the moderate degree of complexity designation from the FDA. Indeed, to obtain such a designation, a system manufacturer must obtain a score of 12 of less when answering 7 questions covering: user knowledge, user training, reagent preparation, operational steps, testing materials, troubleshooting, and result interpretation. The answer to these 7 questions can receive a score of 1 or 3. We estimate our proposed system could get a score of 11. Considering our assay system will not require costly instrumentation and plastic disposables, we believe we can offer a useful alternative to the Xpert GBS(tm), if we can obtain FDA clearance for our test. Support from NIAID is essential to reaching this goal. PUBLIC HEALTH RELEVANCE: Group B streptococcus (GBS) infection of newborns usually takes place in the birth canal and can lead to sepsis, pneumonia, and meningitis. GBS infection of neonates is estimated to cost roughly $300 million in additional healthcare costs. The current "standard of care" is to screen all women at 35 to 37 weeks of gestation, and to eradicate GBS in colonized women. Despite this aggressive approach, invasive early-onset disease incidence has only declined by 34% in the US. Risk factors for early-onset invasive GBS in the newborns are: rupture of membranes more than 18 h before delivery, a febrile mother during labor, preterm delivery, and a history of GBS disease in a previous delivery. Current practice it to prescribe prophylactic antibiotics to mothers with the aforementioned risk profile, even in the absence of evidence of colonization by GBS. Premature rupture of membranes (PROM) occurs in approximately one third of preterm births and it increases the potential for perinatal infection because of its association with brief latency between membrane rupture, and delivery. Preterm pregnancies only represent 7% to 11% of births, but account for 32% to 38% of early-onset GBS disease because the mother was not tested prior to labor. CDC estimates that there are 500,000 pre-term births, and 143,000 births from mothers that received no pre-natal care in the United States. When culture is performed at the time of delivery, it seldom provides a sufficiently rapid turnaround time to influence the decision of whether or not to initiate antimicrobial therapy. A rapid test is clearly needed to test women just before delivery. Unfortunately, current rapid test options are insensitive, too slow, or too costly. Some culture-based tests allow for relatively rapid detection of GBS colonization in heavily colonized women. For example, the FDA cleared StrepB Carrot Broth" (Hardy Diagnostics, Santa Maria, CA) can detect heavy GBS colonization in as little as 6 hours after inoculation of the culture. FDA cleared probe based nucleic acid tests to detect GBS grown in cluture are also commercially available. Unfortunately, 6 hours is too long in many situations. Cepheid's GeneXpert System has obtained FDA clearance for use in laboratories cleared for performing test with "a moderate degree of complexity". This test can yield results in less than 1 hour, but it is far more costly than the slower alternatives. Some physicians have questioned the economic justification for the test. We propose to offer a lower cost molecular assay with an intermediate assay time of ~1 to 2 hours that should also be eligible for being categorized as a moderate degree of complexity assay by FDA.

描述（由申请人提供）：无乳链球菌，又名B群链球菌（GBS），是新生儿发病和死亡的主要原因之一。我们建议使用我们专有的解旋酶依赖性扩增（HDA）开发一种GBS分子检测方法，并在封闭反应容器的装置中嵌入横向流动条，以防止扩增子污染实验室。HDA类似于聚合酶链反应（PCR），它使用两个引物以指数方式扩增核酸。与PCR一样，HDA分析可以使用竞争性内部控制；即，已知浓度的模板DNA加入原始样品中，可以用与分析物相同的引物扩增，但单独检测。与PCR不同，HDA完全是等温的，因此不需要昂贵的热循环器。事实上，我们通常用水浴来进行化验。第一阶段的目标是：1)用一组来自邻近菌株的DNA样本，以及在采样地点常见的菌株，验证检测的敏感性和特异性。2)利用迈阿密大学医学中心（University of Miami Medical Center， UMMC） Gary Procop博士的临床标本，对所提出的过滤制样方法在体内的性能进行评价。3)制定临床计划和预ide，以供美国食品和药物管理局（FDA）审查一项多地点临床研究，以寻求监管部门批准销售用于人类诊断的检测方法。第一阶段的里程碑是向FDA提交预ide。FDA的意见将用于二期临床研究的设计。我们相信我们提出的分析系统可以从FDA获得中等程度的复杂性指定。事实上，要获得这样的称号，系统制造商必须在回答7个问题时获得12分或更少的分数，这些问题包括：用户知识、用户培训、试剂制备、操作步骤、测试材料、故障排除和结果解释。这7个问题的答案可以得到1或3分。我们估计我们提出的系统可以得到11分。考虑到我们的检测系统不需要昂贵的仪器和一次性塑料，我们相信，如果我们的测试能获得FDA的批准，我们可以提供Xpert GBS（tm）的有用替代品。NIAID的支持对实现这一目标至关重要。公共卫生相关性：新生儿B群链球菌（GBS）感染通常发生在产道，可导致败血症、肺炎和脑膜炎。据估计，新生儿感染吉兰-巴雷综合征的额外医疗费用约为3亿美元。目前的“护理标准”是对所有怀孕35至37周的妇女进行筛查，并根除殖民地妇女的GBS。尽管采用了这种积极的方法，侵袭性早发疾病的发病率在美国只下降了34%。新生儿早发性侵袭性GBS的危险因素有：分娩前超过18小时的胎膜破裂、分娩时母亲发热、早产和既往分娩中有GBS病史。目前的做法是给具有上述风险特征的母亲开预防性抗生素，即使没有证据表明存在GBS定植。胎膜早破（PROM）发生在大约三分之一的早产中，它增加了围产期感染的可能性，因为它与胎膜破裂和分娩之间的短暂潜伏期有关。早产仅占出生的7%至11%，但由于母亲在分娩前未进行检测，早产占早发性GBS疾病的32%至38%。美国疾病控制与预防中心估计，美国有50万早产儿，14.3万新生儿的母亲没有接受产前护理。当在分娩时进行培养时，很少能提供足够快的周转时间来影响是否开始抗菌治疗的决定。很明显，需要在分娩前对女性进行快速检测。不幸的是，目前的快速测试选项是不敏感的，太慢，或者太昂贵。一些基于培养的测试可以相对快速地检测出严重感染的妇女的GBS定植。例如，FDA批准的StrepB Carrot Broth”（Hardy Diagnostics, Santa Maria， CA）可以在接种培养物后短短6小时内检测到大量GBS定植。美国食品和药物管理局（FDA）批准的基于探针的核酸检测也可用于检测培养中的GBS。不幸的是，6个小时在很多情况下都太长了。造父变星的GeneXpert系统已经获得了FDA的许可，可以在实验室进行“中等程度的复杂”测试。该测试可以在不到1小时的时间内产生结果，但它比其他较慢的替代方法要昂贵得多。一些医生质疑这项测试的经济合理性。我们建议提供一种成本较低的分子分析方法，中间分析时间约为1至2小时，也应符合FDA将其归类为中等程度复杂性分析的资格。