Pneumococcal transition from nasopharyngeal biofilm carriage to otitis media

肺炎球菌从鼻咽生物膜携带转变为中耳炎

• 批准号: 8997491
• 负责人: Anthony A Campagnari
• 金额: $ 33.88万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT BUFFALO
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8997491
• 关键词: Animal Model; Antimicrobial Resistance; Bacteria; Cessation of life; Child; Coculture Techniques; Complex; Data; Disease; Drug Targeting; Elderly; Environment; Epidemiology; Epithelial Cells; Exposure to; Fever; Gene Expression Profile; Genes; Glucose; Goals; Health; Host Defense; Human; Immunocompromised Host; Impairment; In Vitro; Individual; Infection; Inflammation; Influenza A virus; Integration Host Factors; Language Development; Measurement; Mediating; Methodology; Microbial Biofilms; Modeling; Mus; Nasopharynx; National Institute on Deafness and Other Communication Disorders; Norepinephrine; Nutrient; Otitis Media; Outcome Measure; Pathogenesis; Phenotype; Physiological; Physiology; Pneumococcal Infections; Pneumonia; Population; Process; Production; RNA Sequence Analysis; Respiratory Syncytial Virus Infections; Respiratory syncytial virus; Role; Sepsis; Signal Transduction; Site; Sterility; Streptococcus pneumoniae; Study models; System; Techniques; Temperature; Time; Vaccines; Virulence; Virulence Factors; Virulent; Virus; Virus Diseases; antimicrobial drug; assault; base; cell injury; cognitive development; cold temperature; cytokine; hearing impairment; improved; in vitro Model; in vivo; influenzavirus; middle ear; novel; pathogen; research study; response; transcriptome; transcriptome sequencing

DESCRIPTION (provided by applicant): Streptococcus pneumoniae (the pneumococcus) is an effective colonizer of the human nasopharynx (NP) that on occasion causes disease. However, due to widespread colonization, disease occurs often enough that S. pneumoniae is a leading cause of numerous infections including otitis media (OM) in children, with associated complications, such as hearing loss and impairment of language and cognitive development. Although pneumococcal pathogenesis has been studied for a long time, our understanding of the complex interactions between the human host and bacteria, especially as they relate to colonization and the transition to OM is incomplete. Epidemiologically, transition from colonization to OM is associated with concomitant virus infection or other assaults on the host defense system, but the specific mechanisms involved are not very clear. We recently made the novel observation that pneumococcal NP carriage in vivo is associated with biofilm formation and have shown that recapitulation of this phenotype in vitro requires aspects of the NP environment, including lower temperature, interaction with epithelial cells and limited nutrient availability. Moreover, we have discovered that perturbation of this environment specifically releases bacteria from the biofilm that readily disseminate to the middle ear (ME), causing more severe disease than either biofilm bacteria or bacteria grown in broth and have a unique gene expression profile, that has allowed us to identify several molecules required for bacterial release, dissemination, and induction of OM. The goals of these studies are to mechanistically explore the signals involved in pneumococcal release from NP biofilms (both pneumococcal biofilms and poly-microbial biofilms with common NP colonizing species), dissemination to, and survival in the ME using our novel epithelial cell-based biofilm models and animal models of colonization and infection, and we hypothesize that perturbing the NP environment with dispersants such as increased temperature (fever), nutrients and ATP (associated with cell damage) and virus infection (common disease trigger), that is highly associated with pneumococcal OM will induce release of biofilm bacteria with altered phenotypes associated with increased ability to cause infection of the ME. In the studies delineated herein, we will explore release of bacteria from biofilms in vitro and in vivo after exposure to physiological changes of the normal biofilm/NP environment (Aim 1) or to influenza A virus and respiratory syncytial virus infection (Aim 2). We will then study the ability of bacteria released in vitro or n vivo to induce OM. Finally, we will expand our transcriptome analyses of the bacterial populations using RNA-seq and identify and characterize molecules involved in bacterial biofilm release, dissemination to, and induction of OM (Aim 3). The studies will provide mechanistic information regarding the release of virulent bacteria from biofilms growing in vitro and in vivo and provide specific information of the environmental and bacterial factors responsible for virulence induction in vivo that can be used to inhibit the transition to otitis media.

描述（由申请人提供）：肺炎链球菌（肺炎球菌）是人鼻咽（NP）的有效定植者，有时会引起疾病。然而，由于广泛的殖民化，疾病经常发生，足以使S。肺炎是包括儿童中耳炎（OM）在内的多种感染的主要原因，并伴有相关并发症，如听力丧失和语言及认知发育受损。虽然肺炎球菌的发病机制已经研究了很长一段时间，我们对人类宿主和细菌之间复杂的相互作用的理解，特别是当它们涉及到定植和过渡到OM是不完整的。流行病学上，从定殖到OM的转变与伴随的病毒感染或对宿主防御系统的其他攻击有关，但所涉及的具体机制尚不十分清楚。我们最近进行了新的观察，即肺炎球菌NP携带在体内与生物膜的形成，并已表明，重演这种表型在体外需要NP环境的方面，包括较低的温度，与上皮细胞的相互作用和有限的营养供应。此外，我们已经发现，这种环境的扰动特异性地从生物膜释放细菌，这些细菌容易传播到中耳（ME），导致比生物膜细菌或在肉汤中生长的细菌更严重的疾病，并且具有独特的基因表达谱，这使得我们能够鉴定细菌释放、传播和诱导OM所需的几种分子。这些研究的目的是从机制上探索肺炎球菌从NP生物膜释放的信号（肺炎球菌生物膜和具有常见NP定殖物种的多微生物生物膜），传播到ME和在ME中存活，并且我们假设用分散剂如升高的温度（发烧）扰乱NP环境，营养素和ATP（与细胞损伤有关）和病毒感染与肺炎球菌OM高度相关的肺炎链球菌感染（常见疾病触发因子）将诱导具有改变的表型的生物膜细菌的释放，所述改变的表型与引起ME感染的能力增加相关。在本文描述的研究中，我们将探索在暴露于正常生物膜/NP环境的生理变化后，细菌从体外和体内生物膜中的释放（目的1）或A型流感病毒和呼吸道合胞病毒感染（目的2）。然后，我们将研究体外或体内释放的细菌诱导OM的能力。最后，我们将使用RNA-seq扩展我们对细菌群体的转录组分析，并鉴定和表征参与细菌生物膜释放、传播和诱导OM的分子（目的3）。这些研究将提供关于从体外和体内生长的生物膜中释放有毒细菌的机制信息，并提供负责体内毒力诱导的环境和细菌因素的具体信息，这些信息可用于抑制向中耳炎的转变。