Role of surface proteins in sand fly colonization by Bartonella bacilliformis

表面蛋白在杆状巴尔通体定植白蛉中的作用

• 批准号: 8303852
• 负责人: Michael F Minnick
• 金额: $ 21.23万
• 依托单位: UNIVERSITY OF MONTANA
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8303852
• 关键词: Acute; Address; Adult; Age; Altitude; Americas; Anorexia; Area; Arthralgia; Bacillary Angiomatosis; Bacteremia; Bacteria; Bartonella Infections; Bartonella bacilliformis; Basic Science; Bite; Blood; Bone Pain; Child; Childhood; Chloramphenicol; Chronic; Chronic Disease; Cicatrix; Ciprofloxacin; Colombia; Complement; Confocal Microscopy; Country; Data; Death Rate; Disease; Disease Outbreaks; Ecuador; Epithelium; Erythrocytes; Fever; Flagellin; Fostering; Foundations; Frequencies; Genes; Goals; Gram-Negative Bacteria; Habitats; Headache; Health; Heart murmur; Hemangioma of skin; Hematocrit procedure; Hemolytic Anemia; Hepatomegaly; Histoplasmosis; Human; Icterus; Imaging Techniques; Immigration; Immune response; Immune system; Immunocompromised Host; Incidence; Individual; Infection; Ingestion; Insect Vectors; Insecta; Intervention; Left; Lesion; Life; Location; Lutzomyia genus; Lymphatic Diseases; Malaise; Malaria; Membrane Proteins; Midgut; Molecular; Nature; Neurologic; Oroya Fever; Pallor; Pathogenesis; Patients; Persons; Peru; Phase; Play; Pneumocystis; Population; Populations at Risk; Pregnant Women; Protein C; Public Health; Relative (related person); Reporting; Research; Respiratory Tract Infections; Rifampin; Risk; Role; Salivary Glands; Salmonella infections; Sand Flies; Shigella Infections; Solid; South America; South American; Streptomycin; Syndrome; Techniques; Time; Tissues; Toxoplasmosis; Tropical Disease; Verruga Peruana; Virulence; Virulence Factors; Virulent; Visit; antimicrobial; climate change; design; heme-binding protein; migration; mutant; neglect; novel; pathogen; prevent; protein B; restoration; secondary infection; skin lesion; transmission process; unborn child; vector

DESCRIPTION (provided by applicant): Bartonella bacilliformis (Bb) is a highly virulent, sand fly-borne, gram-negative bacterium that causes bartonellosis (Carri¿n's disease) in humans. Bartonellosis is reemerging in endemic regions (high Andes) and expanding into non-endemic areas (i.e., lower altitudes and more diverse habitats) of Ecuador, Colombia and Peru. The at-risk population is estimated at 1.7 million people in a 56,000 square-mile area of S. America. Incidence rates of 12.7 / 100 person years have been reported in endemic regions. Bb infections can be life threatening, with fatality rates of 40-88%, if left untreated, and 10% fatalty following treatment with antimicrobials. Pediatric populations are especially at risk. In non-endemic regions, the disease manifests as an acute illness with an ~80% reduction in erythrocyte hematocrit (Oroya fever), whereas in endemic regions, angiomatous skin lesions (verruga peruana) and chronic bacteremia prevail, creating a human reservoir of Bb. Little is known about Bb's molecular pathogenesis, virulence determinants and its association with the sand fly vector, Lutzomyia verrucarum. To address this dearth of information, we propose to examine Bb's relationship with L. verrucarum, by live imaging techniques. We also propose to examine the role of three putative virulence determinants [i.e., flagellin (FlaA), heme-binding protein C (HbpC) and the invasion-associated locus B (IalB) protein] in Bb's colonization of L. verrucarum. We hypothesize that Bb initially infects the insect's midgut epithelium upon ingestion of a contaminated blood-meal. From this focus of infection, the hemocoel and eventually the salivary glands become infected, owing to the highly invasive nature of Bb, and that the resulting infection is life-long and not trans-ovarially transmitted. Finally, we hypothesze that Bb mutants which lack the aforementioned virulence factors will be impaired in their ability to colonize, replicate and/or spread in the sand fly. To address these hypotheses, we propose the flowing aims: In Aim 1, we will analyze colonization and migration of a low-passage, GFP+ Bb strain in sand flies. The first goal is to generate a low-passage Bb strain that contains a stable, GFP-expressing insert. The second goal is to follow the anatomical locations of the GFP+ Bb strain in the sand fly over time, by confocal microscopy. In Aim 2, we will generate hbpC, ialB and flaA mutants in low-passage Bb strains. The first goal is to generate low-passage, Bb strains whose hbpC, ialB and flaA virulence determinants have been mutagenized by a novel technique. The second goal is to create corresponding, complemented strains by allelic restoration. In Aim 3, we will compare wild-type (WT), mutant and complemented Bb strains for the ability to colonize and persist in sand flies. The first goal is to compare the reltive ability of these Bb strains to colonize sand flies. The second goal is to compare the ability of these strains to replicate and persist in the sand fly. Aim 3 results will be used to address molecular Koch's postulates for these genes, as it relates to the sand fly vector. The results of the study are expected to provide a solid foundation for eventually developing control strategies designed to interrupt the sand fly-Bb association. PUBLIC HEALTH RELEVANCE: Bartonella bacilliformis is the sand fly-borne, bacterial agent of bartonellosis (Carri¿n's disease) in humans; a neglected tropical disease that threatens ~1.7 million people in 56,000 square miles of South America. The proposed research will analyze B. bacilliformis colonization and migration in the sand fly vector and will compare these activities i wild-type and mutant strains of the bacterium that lack one of three determinants hypothesized to be involved in virulence, including flagellin (FlaA), heme-binding protein C (HbpC) and invasion-associated locus B (IalB) proteins. In addition to addressing a dearth of information on the bacterium's pathogenesis and association with its insect vector, results of the study will establish a foundation for the long- range goal of developing strategies that disrupt the sand fly-pathogen association and prevent transmission to humans.

描述（由适用提供）：Bartonella芽孢杆菌（BB）是一种高毒，砂蝇，革兰氏阴性细菌，在人类中导致Bartonellosis（Carri¿n病）。 Bartonellosis正在流行地区（高安第斯山脉）重新出现，并扩展到厄瓜多尔，哥伦比亚和秘鲁的非末端区域（即较低的海拔和更多的潜水栖息地）。在56,000平方英里的S.美国。在内在区域报告了12.7 / 100人年的发病率。 BB感染可能会危及生命，如果未治疗，死亡率为40-88％，用抗菌素治疗后10％的致命性。小儿种群特别有风险。在非内态区域中，该疾病表现为急性疾病，红细胞血细胞比容降低了约80％，而在地方性地区，血管瘤皮肤病变（Verruga Peruana）（Verruga Peruana）和慢性细菌中，造成了BB的人体储备。关于BB的分子发病机理，确定病毒及其与沙蝇载体Lutzomyia verrucarum的关联知之甚少。为了解决信息的死亡，我们建议通过实时成像技术研究BB与L. verrucarum的关系。我们还建议研究三种假定病毒决定剂[即鞭毛蛋白（FLAA），血红素结合蛋白C（HBPC）和与入侵相关的基因座B（IALB）蛋白]在BB的L. verrucarum殖民化中的作用。我们假设BB最初在摄入受污染的血液中感染了昆虫的中肠上皮。从这种感染的重点，由于BB的高度侵入性性质，血液和最终的唾液场被感染，并且所致的感染是终生且不跨性别地传播的。最后，我们假设缺乏优先病毒因子的BB突变体在定居，复制和/或在沙蝇中分布的能力会受到损害。为了解决这些假设，我们提出了流动的目的：在AIM 1中，我们将分析砂蝇中低通量的GFP+ BB菌株的定植和迁移。第一个目标是生成一个含有稳定的表达GFP插入物的低通bb菌株。第二个目标是通过共聚焦显微镜遵循沙子中GFP+ Bb菌株的解剖位置。在AIM 2中，我们将在低通量BB菌株中生成HBPC，ALB和FLAA突变体。第一个目标是生成低通量的BB菌株，其HBPC，ALB和FLAA病毒确定剂已通过一种新技术进行了诱变。第二个目标是通过等位基因修复创建相应的，完成的应变。在AIM 3中，我们将比较野生型（WT），突变体和完成的BB菌株，以便在沙蝇中定居和持续存在。第一个目标是比较这些BB菌株的可靠性以殖民沙子。第二个目标是比较这些菌株在沙子中复制和持续存在的能力。 AIM 3结果将用于解决这些基因的分子Koch假设，因为它与沙蝇载体有关。该研究的结果有望为最终开发旨在中断沙蝇BB关联的控制策略提供稳固的基础。 公共卫生相关性：Bartonella bacilliformis是Sand Fly-borne，这是人类Bartonellisos（Carri¿n病）的细菌剂；一种被忽视的热带疾病威胁到南美56,000平方英里的约170万人。拟议的研究将分析砂蝇载体中的细菌芽孢杆菌的定殖和迁移，并将比较细菌的野生型和突变菌株，这些活动缺乏三种决定涉及病毒的决定因素之一，包括鞭毛蛋白（FLAA）（FLAA），血腥结合蛋白C（HBPC）和ivision-Invision-IntabissIdip sassiped-systrip ofteb（iameb）（iameb）（iameb）（iaim b）。除了解决有关细菌发病机理的信息死亡以及与昆虫载体的关联之外，该研究的结果还将为开发策略的远程目标建立基础，以开发破坏沙蝇 - 病原体关联并防止向人类传播的策略。