Quorum Sensing in H. influenzae otitis

流感嗜血杆菌中耳炎的群体感应

• 批准号: 6576267
• 负责人: Arnold Lee Smith
• 金额: $ 40.28万
• 依托单位: SEATTLE BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-20 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6576267
• 关键词: Haemophilus influenzae; bacteria infection mechanism; bacterial cytopathogenic effect; bacterial genetics; beta lactam antibiotic; beta lactamase; chinchilla; chloramphenicol acetyltransferase; enzyme linked immunosorbent assay; gene expression; host organism interaction; laboratory rat; macrolide antibiotics; mucins; mutant; otitis media; phase contrast microscopy; plasmids; protein biosynthesis; quinoline; serum; tetracyclines; tissue /cell culture; transcription factor; transfection; virulence

DESCRIPTION (provided by applicant): Otitis media with effusion (OME) is a significant health problem of children. Haemophilus influenzae is one of the major causes of this disease. Features of H. influenzae OME include frequent recurrences and a failure of eradication with antibiotic administration. One hypothesis explaining these features of H. influenzae OME is that the organism is growing as a biofilm in the middle ear. Bacterial biofilms are characteristically insensitive to antibiotic treatment, as well as incapable of elimination by the host inflammatory response. Evidence of a H. influenzae biofilm in children with OME consists of the presence of short-lived, Haemophilus-specific mRNA in the middle ear fluid of these children. Gram-negative bacterial biofilm formation is dependent upon the synthesis of quorum-sensing transcriptional activators, called autoinducers. We have found that H. influenzae; including those isolated from the middle ear possess a gene (HI0491) capable of synthesizing an autoinducer (AI-2). Insertional inactivation of HI0491 in the H. influenzae laboratory strain Rd KW20 results in a mutant, which lacks the ability to form mature biofilm structures, and has decreased susceptibility to antibiotics, a decreased conjugation frequency and decreased survival in an animal model of OME. In this application, we are seeking to characterize biofilm formation by several prototypic "otitic" H. influenzae in vitro, assess experimental OME caused by these strains in the weanling rat and chinchillas, determine the role of the autoinducer in this disease and define the role of AI-2 in biofilm development in vitro and in vivo. Understanding the role of AI-2 and biofilm formation in OME will permit strategies to prevent or treat this disease to be devised.

描述（由申请人提供）：渗出性中耳炎（OME）是儿童的一个重要健康问题。流感嗜血杆菌是引起这种疾病的主要原因之一。H.流感OME包括频繁复发和使用抗生素根除失败。一个假说解释了H.流感OME是生物体在中耳中作为生物膜生长。细菌生物膜的特征是对抗生素治疗不敏感，并且不能通过宿主炎症反应消除。有H的证据。OME患儿的流感生物膜由这些患儿中耳液中存在的短暂的嗜血杆菌特异性mRNA组成。革兰氏阴性细菌生物膜的形成依赖于群体感应转录激活因子（称为自诱导因子）的合成。我们发现H.流感病毒;包括从中耳分离的那些具有能够合成自身诱导物（AI-2）的基因（HI 0491）。HI 0491在H.流感实验室菌株Rd KW 20导致突变体，其缺乏形成成熟生物膜结构的能力，并且在OME的动物模型中对抗生素的敏感性降低、接合频率降低和存活率降低。 在本申请中，我们试图通过几种原型“耳炎”H.本发明的目的是在体外研究流感病毒，评估由这些菌株在断奶大鼠和灰鼠中引起的实验OME，确定自诱导物在这种疾病中的作用，并确定AI-2在体外和体内生物膜发育中的作用。了解AI-2和生物膜形成在OME中的作用将允许设计预防或治疗这种疾病的策略。