Virulence genes Haemophilus influenzae

流感嗜血杆菌毒力基因

• 批准号: 6435257
• 负责人: Arnold Lee Smith
• 金额: --
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2002-09-16
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6435257
• 关键词: Haemophilus influenzae; adhesin; bacterial DNA; bacterial disease; bacterial genetics; genetic library; genetically modified animals; genome; laboratory mouse; laboratory rat; meningitis; mutant; nasopharynx; nucleic acid sequence; polymerase chain reaction; respiratory epithelium; southern blotting; structural genes; tissue /cell culture; toxin; virulence; western blottings

DESCRIPTION (provided by applicant): Haemophilus influenzae is a human-restricted bacterium which can exist as an upper respiratory commensal, but also cause focal and/or systemic disease. More than 95 percent of the nasopharyngeal isolates lack capsules and are not serotypeable, and cause focal infections, while encapsulated (and rare nontypeable) strains cause sepsis and meningitis. The genome of both commensal and pathogenic isolates is 250 kb (on average) larger than the avirulent laboratory strain (Rd KW2O) whose genome sequence was published in 1995. We have found that the genome of strain Rd KW2O is a "scaffold" on which genes, gene clusters and operons encoding virulence factors are inserted, usually at the Haemophilus-specific DNA uptake sites. Using differential hybridization we will identify those DNA loci that permit nasopharyngeal colonization by commensals, and the additional putative virulence loci in pathogenic isolates. Each of these DNA fragments and the flanking DNA, will be sequenced until the Rd KW2O scaffold is identified. All sequence information will be posted on the UW Genome Center web site. Using strict criteria for homology (not conventional criteria) putative virulence genes will either be deleted or mutated and the virulence of the mutant compared to the parent in a relevant in vitro and/or in vivo infection model. For example a putative adhesin present in a lower respiratory tract isolate could be tested with human respiratory epithelial cell lines, and with primary human respiratory epithelium growing at an air-liquid interface in tissue culture. One unique isolate, an untypeable strain causing meningitis in an immunocompetent child immunized with a Hib-conjugate vaccine appears to be a member of a clade; we wish to confirm the preliminary finding and initiate a global database (in collaboration with the MLST Haemophilus Center) for these vaccine-failure isolates. With an understanding of the molecular mechanisms of colonization versus infection, strategies for prevention and intervention can be devised.

性状（由申请方提供）：流感嗜血杆菌是一种 人类限制性细菌，其可以作为上呼吸道寄生虫存在， 而且还引起局灶性和/或全身性疾病。超过95%的 鼻咽分离物缺乏胶囊，并且不典型，并且引起局灶性 感染，而封装（和罕见的不可分型）菌株引起败血症， 脑膜炎致病性和非致病性分离物的基因组均为250 kb（约 平均）大于无毒力实验室菌株（Rd KW 2 O），其基因组 序列发表于1995年。我们已经发现菌株Rd KW 20的基因组 是一个“支架”，基因，基因簇和操纵子编码毒力 通常在嗜血杆菌特异性DNA摄取位点插入因子。 使用差异杂交，我们将确定那些DNA位点， 鼻咽定殖的细菌，以及其他假定的 致病菌株的毒力位点。每一个DNA片段 侧翼DNA，将被测序，直到确定Rd KW 2 O支架。所有 序列信息将公布在华盛顿大学基因组中心网站上。使用 同源性的严格标准（非常规标准）推定毒力 基因将被删除或突变，突变体的毒力 在相关的体外和/或体内感染模型中与母体相比。 例如，下呼吸道分离株中存在的假定粘附素 可以用人类呼吸道上皮细胞系进行测试， 在组织中的气-液界面处生长的人呼吸上皮 文化一种独特的分离物，一种无法分型的菌株， 用Hib-conjugate疫苗免疫的免疫活性儿童似乎是 一个分支的成员;我们希望确认初步的发现，并启动一个 全球数据库（与MLST嗜血杆菌中心合作） 疫苗失效分离株随着对分子机制的理解， 殖民化与感染，预防和干预战略， 被设计。