Quorum Sensing in H. influenzae otitis

描述（由申请人提供）：渗出性中耳炎（OME）是儿童的重要健康问题。流感嗜血杆菌是该病的主要病因之一。流感嗜血杆菌OME的特征包括频繁复发和抗生素治疗根除失败。一种解释流感嗜血杆菌OME这些特征的假说是，这种有机体在中耳中以生物膜的形式生长。细菌生物膜的特点是对抗生素治疗不敏感，也不能被宿主的炎症反应消除。OME患儿存在流感嗜血杆菌生物膜的证据包括这些患儿中耳液中存在短暂的嗜血杆菌特异性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因子的合成，称为自诱导剂。我们发现流感嗜血杆菌；包括从中耳分离的具有能够合成自诱导剂（AI-2）的基因（HI0491）。HI0491在流感嗜血杆菌实验室菌株Rd KW20中的插入失活导致突变，该突变缺乏形成成熟生物膜结构的能力，并且在OME动物模型中对抗生素的敏感性降低，偶联频率降低，存活率降低。

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.