Rapid sensitive low cost test for resistant microbes causing hospital infections

描述（由申请人提供）：我们建议开发一种新的测试平台，以实现快速，超灵敏，准确，用户友好且具有成本效益的筛查抗生素耐药细菌，这些细菌经常导致严重的医院获得性感染。每年有近10万人死于200万例严重的医院获得性感染，估计造成的损失为305亿美元。这些死亡中约有2万人是由耐甲氧西林金黄色葡萄球菌（MRSA）引起的。在过去的30年里，医院获得性感染率和MRSA的传播都急剧增加。现在很多人身上都携带MRSA，即使是健康的人。当MRSA携带者住院时，耐药微生物会对携带者和医院里的其他人造成严重感染。最近的研究表明，医院可以通过对住院病人进行MRSA筛查，然后使用包括隔离在内的严格感染控制程序对他们进行治疗，从而大大减少医院获得性感染的发生。筛选MRSA患者的传统微生物学方法非常缓慢，需要数天时间，因此与快速识别和分离MRSA携带者不相容。新的基于核酸扩增的MRSA快速检测在某些部位被用于MRSA筛查。然而，这些检测昂贵、复杂，因此目前不适用于大多数医院的大规模筛查。我们的目标是开发一种新的快速、敏感、易于使用的系统，用于大规模的低成本MRSA筛查。该系统的专利技术使用低成本的非放大数字成像技术来计数带有高荧光颗粒的金黄色葡萄球菌细胞。该测试确定样品中金黄色葡萄球菌细胞的初始数量，以及在含抗生素的选择性培养基中孵育数小时后金黄色葡萄球菌细胞的数量。只有当样品中含有MRSA时，抗生素的存在才会使金黄色葡萄球菌细胞数量显著增加。与基于基因型核酸的检测相比，这种基于表型生长的方法的一个优点是，它可以应用于任何类型的微生物和任何抗生素。具体目标是：(1)开发金黄色葡萄球菌特异性颗粒试剂和MRSA筛选方法；(2)开发一个自动化的原型系统，包括一个成像仪器和一个含试剂的墨盒；(3)论证检测性能，并与临床样本的培养和核酸扩增参考方法进行比较。实现这些具体目标应该证明第二阶段项目的合理，该项目将重点扩展MRSA检测到其他样品类型（如伤口、软组织、血液），开发其他导致医院获得性感染的重要药物（如耐万古霉素肠球菌、艰难梭菌）的测试，并开发用于MRSA筛查的预商业化原型仪器/消耗性系统。除了检测耐药微生物的价值外，该系统还具有其他重要细胞检测应用的商业潜力，包括检测病毒感染细胞、CD4+细胞（用于监测艾滋病毒状态）、食品病原体和药物发现。用于筛选耐药细菌的商业化多路径系统将有助于降低医院获得性感染率。每年约有200万例医院获得性感染导致近2万人死亡，医疗保健系统每年损失约300亿美元。新系统将使更多的医院能够实施快速检测，从而改善感染控制并降低医院获得性感染率。

DESCRIPTION (provided by applicant): We propose to develop a novel testing platform to enable rapid, ultrasensitive, accurate, user-friendly, and cost-effective screening for the antibiotic resistant bacteria that frequently cause serious hospital acquired infections. Every year, nearly 100,000 deaths result from 2 million serious hospital acquired infections at an estimated cost of $30.5B. About 20,000 of these fatalities are caused by methicillin-resistant Staphylococcus aureus bacteria (MRSA). Both the rate of hospital acquired infections and the spread of MRSA have increased dramatically in the last 30 years. Many individuals now carry MRSA on their bodies, even when healthy. When MRSA carriers are hospitalized the resistant microbe can cause serious infections for the carrier and others in the hospital. Recent studies have shown that hospitals can substantially decrease the occurrence of hospital acquired infections by screening admitted patients for MRSA and then treating them using rigorous infection control procedures including isolation. Traditional microbiological methods for screening patients for MRSA are very slow, requiring several days, and are therefore incompatible with rapid identification and isolation of MRSA carriers. New rapid MRSA tests based on nucleic acid amplification are used for MRSA screening at some sites. However these tests are expensive, complex and thus not currently practical for large scale screening in most hospitals. We aim to develop a novel rapid, sensitive, and easy-to-use system for large scale cost-effective MRSA screening. The system's proprietary technology uses low-cost non-magnified digital imaging to count individual S. aureus cells specifically tagged with highly fluorescent particles. The test determines the initial number of S. aureus cells in the sample and the number of S aureus cells after incubation for several hours in antibiotic-containing selective media. Only if the sample contains MRSA, will there be a significant in- crease in S. aureus cell number in the presence of antibiotic. An advantage of this phenotypic growth-based approach over genotypic nucleic acid-based tests is that it can be applied to any type of microbe and any anti- biotic. The Specific Aims are to (1) develop S. aureus-specific particle reagents and the MRSA screening as- say method; (2) develop an automated prototype system including an imaging instrument and a reagent- containing cartridge; and (3) demonstrate assay performance and compare it to the culture and nucleic acid amplification reference methods using clinical samples. Achieving these Specific Aims should justify a Phase 2 project that will focus on extending the MRSA assay to other sample types (e.g., wound, soft tissue, blood), developing tests for other important agents that cause hospital acquired infection agents (e.g., vancomycin resistant Enterococcus, C. difficile), and developing a pre-commercial prototype instrument/consumable system for MRSA screening. Besides its value for detecting resistant microbes, the system has commercial potential for other important cellular detection applications including detecting virally infected cells, CD4+ cells (for monitoring HIV status), food pathogens, and in drug discovery. PUBLIC HEALTH RELEVANCE The commercialized MultiPath system for screening for resistant bacteria will help lower the rate of hospital acquired infections. The approximately 2 million hospital acquired infections that occur per year cause nearly 20,000 deaths and cost the healthcare system about $30B a year. The new system will enable more hospitals to implement rapid testing, which in turn leads to improved infection control and lower hospital acquired infection rates.