Molecular epidemiologic identification of pneumococcal tissue specific genes

肺炎球菌组织特异性基因的分子流行病学鉴定

• 批准号: 7587469
• 负责人: Melinda Mary Pettigrew
• 金额: $ 56.74万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7587469
• 关键词: 2 year old; 5 year old; Bacteremia; Bacteria; Blood; Cerebrospinal Fluid; Characteristics; Child; Chinchilla (genus); Clinical; Collection; DNA Sequence; Disease; Dot Immunoblotting; Epidemiology; Genes; Genetic; Genetic Determinism; Genomics; Genotype; Hereditary Disease; Human; Individual; Infection; Invaded; Laboratories; Left; Meningitis; Methods; Modeling; Molecular; Molecular Epidemiology; Nasopharynx; Otitis Media; Pathogenesis; Pneumonia; Population; Predisposing Factor; Relative (related person); Research Personnel; Respiratory System; Respiratory tract structure; Role; Site; Sterility; Streptococcus pneumoniae; Testing; Tissues; Virulence; Virulence Factors; clinically relevant; middle ear; mutant; population based; prevent; programs

DESCRIPTION (provided by applicant): Streptococcus pneumoniae inhabits the human respiratory tract and causes disease when it leaves the nasopharyngeal region and invades normally sterile sites. Asymptomatic carriage is far more common than disease, yet these bacteria are important causes of otitis media, pneumonia, meningitis, and bacteremia in young children. Despite advances in our understanding of the epidemiology and pathogenesis of these bacteria, the precise factors that predispose a pneumococcal strain for carriage versus disease are not known. S. pneumoniae strains differ in their propensity to cause disease, and the genetic background of a particular strain is likely to influence its ability to successfully invade different tissue sites. We propose an interdisciplinary molecular and epidemiologic approach to increase understanding of the differences between pneumococcal carriage and clinical isolates. Our overall aims are 1) to determine the molecular epidemiology of S. pneumoniae clinical and carriage isolates from children <5 years of age; 2) to identify tissue specific virulence factors associated with S. pneumoniae strains that cause clinical disease in children <5 years of age and evaluate their distribution among a large collection of clinical and carriage strains; and 3) to evaluate candidate otitis media specific virulence genes in the chinchilla model of otitis media. Specifically, we will determine the association of S. pneumoniae clones with carriage and specific clinical diseases using multilocus sequence typing, identify individual genetic determinants of tissue specific virulence using genomic subtraction, and evaluate the relative importance of these putative virulence determinants at the population level using a dot blot hybridization screen of a large, clinically relevant collection of pneumococcal isolates. These isolates are from healthy children and children with bacteremia, pneumonia, meningitis and otitis media. S. pnueumoniae deletion mutants in otitis media associated genes will be created and their virulence tested in an experimental chinchilla model of otitis media. A greater understanding of the genetic factors that influence the virulence potential of pneumococcal clones is critical to our ability to develop effective methods to control, prevent, and treat these important infections.

描述（由申请人提供）：肺炎链球菌寄生于人的呼吸道，当它离开鼻咽区并侵入通常无菌的部位时引起疾病。无症状携带远比疾病更常见，但这些细菌是幼儿中耳炎、肺炎、脑膜炎和菌血症的重要原因。尽管我们对这些细菌的流行病学和发病机制的了解有所进展，但导致肺炎球菌菌株携带与疾病的确切因素尚不清楚。肺炎链球菌菌株引起疾病的倾向不同，特定菌株的遗传背景可能会影响其成功侵入不同组织部位的能力。我们提出一种跨学科的分子和流行病学方法，以增加对肺炎球菌携带和临床分离株之间差异的理解。我们的总体目标是：1)确定5岁以下儿童肺炎链球菌临床和携带分离株的分子流行病学；2)鉴定与导致5岁以下儿童临床疾病的肺炎链球菌菌株相关的组织特异性毒力因子，并评估其在大量临床和携带菌株中的分布；3)评价中耳炎鼠模型中耳炎候选毒力基因。具体而言，我们将使用多位点序列分型确定肺炎链球菌克隆与携带和特定临床疾病的关联，使用基因组减法确定组织特异性毒力的个体遗传决定因素，并使用大量临床相关肺炎球菌分离株的斑点杂交筛选评估这些假定的毒力决定因素在群体水平上的相对重要性。这些分离物来自健康儿童和患有菌血症、肺炎、脑膜炎和中耳炎的儿童。将在中耳炎相关基因中创建肺炎链球菌缺失突变体，并在中耳炎实验栗鼠模型中检测其毒力。更好地了解影响肺炎球菌克隆潜在毒力的遗传因素对我们开发有效方法来控制、预防和治疗这些重要感染的能力至关重要。