Quorum Sensing in H. influenzae otitis

流感嗜血杆菌中耳炎的群体感应

• 批准号: 6793725
• 负责人: Arnold Lee Smith
• 金额: $ 42.98万
• 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/6793725
• 关键词: Haemophilus influenzae; bacteria infection mechanism; bacterial cytopathogenic effect; bacterial genetics; beta lactam antibiotic; beta lactamase; biofilm; 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(申请人提供)：渗出性中耳炎(OME)是一个严重的儿童健康问题。流感嗜血杆菌是引起本病的主要原因之一。流感嗜血杆菌OME的特征包括频繁复发和使用抗生素根除失败。解释流感嗜血杆菌OME这些特征的一个假设是，这种有机体在中耳作为生物膜生长。细菌生物膜对抗生素治疗不敏感，也不能被宿主炎症反应消除。在患有OME的儿童中，流感嗜血杆菌生物被膜的证据包括在这些儿童的中耳液中存在短暂的、嗜血杆菌特异性的mRNA。革兰氏阴性细菌生物膜的形成依赖于群体感应转录激活剂的合成，称为自体诱导剂。我们发现，流感嗜血杆菌；包括从中耳分离的流感嗜血杆菌，拥有一种能够合成自身诱导物(AI-2)的基因(HI0491)。在流感嗜血杆菌实验室菌株RD KW20中插入失活HI0491会导致突变，缺乏形成成熟生物膜结构的能力，并降低了对抗生素的敏感性，接合频率降低，OME动物模型中的存活率下降。 在这项应用中，我们试图在体外表征几种原型的流感嗜血杆菌的生物膜形成，评估这些菌株在断奶大鼠和龙猫身上引起的实验性OME，确定自身诱导剂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中的作用将有助于制定预防或治疗这种疾病的策略。