Virulence genes Haemophilus influenzae

流感嗜血杆菌毒力基因

基本信息

批准号：
6711189
负责人：
Arnold Lee Smith
金额：
$ 34.08万
依托单位：
SEATTLE BIOMEDICAL RESEARCH INSTITUTE
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-09-17 至 2006-02-28
项目状态：
已结题

项目摘要

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.

描述（由申请人提供）：流感嗜血杆菌是人限制的细菌可以作为上呼吸道共同存在，但也会引起局灶性和/或全身性疾病。超过95％鼻咽分离株缺乏胶囊，不可用血清型，并且引起焦点感染，虽然封装（且罕见的不可用）菌株会引起败血症和脑膜炎。共生和致病性分离株的基因组为250 kb（on 平均）比无毒性实验室应变（RD KW2O）大的基因组（RD KW2O）序列于1995年发表。我们发现菌株RD KW2O的基因组是一个“脚手架” 通常在嗜血杆菌特异性的DNA吸收位点插入因子。使用差异杂交我们将确定允许的DNA基因座鼻咽殖民地的鼻咽定植和额外的推定致病分离株中的毒力基因座。这些DNA碎片和侧翼DNA将进行测序，直到确定RD KW2O支架。全部序列信息将发布在UW基因组中心网站上。使用同源性的严格标准（不是常规标准）推定的毒力基因将被删除或突变，并且突变体的毒力在相关的体外和/或体内感染模型中与父母相比。例如，下呼吸道分离物中存在的推定粘合剂可以用人类呼吸道上皮细胞系进行测试，并且在组织中生长在空气界面上的人呼吸道上皮文化。一个独特的分离株，一种不可用的菌株，导致脑膜炎免疫能力的儿童用Hib偶联疫苗免疫似乎是一种进化枝的成员；我们希望确认初步发现并启动全球数据库（与MLST嗜血杆菌中心合作）疫苗失败分离株。了解殖民与感染，预防和干预策略可以被设计。