Optimizing the diagnosis of pediatric Clostridium difficile infection

 描述(由申请人提供)：艰难梭菌感染(CDI)是最常见的医疗保健相关感染(HAI)之一。尽管儿童CDI的发病率在上升，但对儿童CDI的研究相对有限。在儿童中诊断CDI非常具有挑战性，特别是因为儿童通常是艰难梭菌的无症状携带者。核酸扩增试验(NAAT)在美国儿童医院最常用于诊断CDI，主要是因为成人研究表明毒素酶免疫分析(EIA)的敏感性不佳。NAAT高度敏感，在无症状携带者的儿童中也能检测到艰难梭菌。因此，NAAT阳性并不一定表明艰难梭菌是 儿童腹泻和CDI在携带者中误诊的原因是使用NAAT的常见后果。为了克服NAAT和EIA的局限性，最近开发的一种超灵敏毒素检测正在成年患者中进行研究。CDI误诊导致携带者不必要地使用CDI抗生素，增加了医疗成本、抗生素耐药性和不良事件。CDI误诊也影响了对儿科CDI的研究。因此，有必要改进CDI诊断策略，以改善对这种常见的HAI的患者护理，并减少未来CDI调查中的误分类偏差。为了应对这些挑战，拟议的研究旨在全面评估各种实验室方法，以更好地区分CDI和CARY，从而改善儿童CDI的诊断。此外，利用全基因组测序(WGS)，我们的目标是识别引起CDI和CART的菌株之间的基因组差异，以揭示引起CART或CDI的菌株所特有的基因组靶标，这些靶标可以适用于CDI诊断测试。具体地说，我们的目标是：(1)确定诊断患有腹泻的儿童CDI的最佳测试策略；(2)确定各种NAAT在无腹泻的儿童中识别艰难梭菌携带的相对倾向；以及(3)使用WGS，(A)识别从儿童中分离的艰难梭菌的基因类型；以及(B)识别CDI和携带的基因组生物标记物。在Alan Hauser医学博士和Dale Gerding医学博士的共同指导下，Larry Kociolek医学博士寻求在他之前CDI翻译研究经验的基础上再接再厉。Kociolek博士将学习艰难梭菌特征的基因组方法，以及将病原体基因组数据应用于面向患者的研究的方法。Kociolek博士的主要职业目标是成为儿科CDI研究的领导者，并协调合作努力，以减轻儿童CDI的负担。芝加哥安和罗伯特·H·鲁里儿童医院和西北大学范伯格医学院卓越的综合研究基础设施将有助于实现他的学术目标。未来的研究方向包括协调一项多中心儿科研究，以验证最佳的CDI诊断策略，并随后确定导致儿童CDI及其并发症的宿主和病原体因素。这些数据对于指导未来儿童CDI预防和治疗策略的临床试验至关重要。

 DESCRIPTION (provided by applicant): Clostridium difficile infection (CDI) is one of the most common healthcare-associated infections (HAI). Despite rising CDI incidence in children, studies of pediatric CDI are relatively limited. Diagnosing CDI in children is very challenging, particularly because children are commonly asymptomatic carriers of C. difficile. Nucleic acid amplification tests (NAATs) are most commonly used to diagnose CDI at US children's hospitals, primarily because of adult studies suggesting suboptimal sensitivity of toxin enzyme immunoassays (EIAs). NAATs are highly sensitive and also detect C. difficile in children who are asymptomatic carriers. Thus, NAAT positivity does not necessarily indicate that C. difficile is the cause of a child's diarrhea, and CDI misdiagnosis among carriers is a common consequence of using NAATs. To overcome the limitations of both NAATs and EIAs, a recently developed ultrasensitive toxin assay is under investigation in adult patients. CDI misdiagnosis leads to unnecessary antibiotic utilization for CDI among carriers, increasing healthcare costs, antibiotic resistance, and adverse events. CDI misdiagnosis also biases investigation of pediatric CDI. Therefore, improved CDI diagnostic strategies are necessary to improve patient care for this common HAI and reduce misclassification bias in future CDI investigation in children. To address these challenges, the proposed study aims to comprehensively evaluate various laboratory methodologies to better differentiate CDI and carriage, resulting in improved CDI diagnosis in children. In addition, using whole genome sequencing (WGS), we aim to identify genomic differences between strains causing CDI and carriage that may reveal genomic targets unique to strains causing carriage or CDI that can be adapted for CDI diagnostic testing. Specifically, we aim to: (1) Define the optimal testing strategy for diagnosing CDI in children wit diarrhea; (2) Determine the relative propensity of various NAATs to identify C. difficile carriage in children without diarrhea; and (3) Using WGS, (a) Identify C. difficile genotypes isolated from children; and (b) Identify genomic biomarkers of CDI and carriage. With co-mentorship from Alan Hauser, MD, PhD and Dale Gerding, MD, Larry Kociolek, MD seeks to build upon his previous CDI translational research experience. Dr. Kociolek will learn genomic methods of C. difficile characterization and methods for applying pathogen genomic data to patient-oriented research. Dr. Kociolek's overarching career goal is to become a leader in the investigation of pediatric CDI and coordinate collaborative efforts to reduce CDI burden in children. The excellent integrated research infrastructure at the Ann & Robert H. Lurie Children's Hospital of Chicago and Northwestern University Feinberg School of Medicine will facilitate achievement of his academic goals. Future research directions include coordinating a multi-center pediatric study to validate optimal CDI diagnostic strategies and subsequently identifying both host and pathogen factors that contribute to CDI and its complications in children. These data are essential for guiding future clinical trials of preventive and therapeutic strategies for CDI in children.