Rapid sensitive low cost test for resistant microbes causing hospital infections

描述(申请人提供)：我们建议开发一种新的测试平台，以实现对经常导致严重医院获得性感染的抗生素耐药细菌的快速、超敏感、准确、用户友好和成本效益的筛选。每年有近10万人死于200万例严重的医院感染，估计费用为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耐甲氧西林金黄色葡萄球菌的传播都急剧增加。许多人现在携带着MRSA，即使在健康的情况下也是如此。当MRSA携带者住院时，耐药微生物可能会对携带者和医院内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患者进行MRSA筛查，然后使用包括隔离在内的严格感染控制程序来治疗，从而大大减少医院获得性感染的发生。传统的微生物学方法筛查MRSA患者的速度非常慢，需要几天时间，因此与MRSA携带者的快速鉴定和分离不兼容。新的基于核酸扩增的快速MRSA检测方法被用于某些地点的MRSA筛查。然而，这些测试昂贵、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、灵敏和易于使用的系统，用于大规模低成本的MRSA筛查。该系统的专利技术使用低成本、非放大的数字成像来计数个别金黄色葡萄球菌细胞，这些细胞专门标记了高度荧光的颗粒。这项测试确定了样本中初始金黄色葡萄球菌细胞的数量，以及在含抗生素的选择性培养液中孵育几个小时后S金黄色葡萄球菌细胞的数量。只有当标本中含有MRSA时，在抗生素存在的情况下，金黄色葡萄球菌的细胞数量才会显著增加。这种基于表型生长的方法与基于基因核酸的测试相比的一个优点是，它可以应用于任何类型的微生物和任何抗菌素。其具体目标是(1)开发金黄色葡萄球菌特异性颗粒试剂和MRSA筛查方法；(2)开发包括成像仪和试剂盒在内的自动化原型系统；(3)展示检测性能，并将其与临床样本的培养和核酸扩增参考方法进行比较。为了实现这些具体目标，应证明第二阶段项目是合理的，该项目将侧重于将MRSA检测扩展到其他样本类型(例如伤口、软组织、血液)，开发对导致医院获得性感染因素(例如万古霉素耐药肠球菌、艰难梭菌)的其他重要因素的测试，并开发用于MRSA筛查的商业化前原型仪器/消耗品系统。除了检测耐药微生物的价值外，该系统还具有其他重要的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HIV状态)、食品病原体和药物开发。公共卫生相关性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。每年发生的大约200万医院获得性感染导致近2万人死亡，医疗保健系统每年花费约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，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.