Ecological population structure and emergence of virulent Vibrio parahaemolyticus

副溶血弧菌的生态种群结构和强毒力的出现

• 批准号: 7847548
• 负责人: Vaughn Cooper
• 金额: $ 7万
• 依托单位: UNIVERSITY OF NEW HAMPSHIRE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-05-22 至 2011-10-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7847548
• 关键词: Acute; Address; Area; Bacteria; Biological Assay; Biology; Carbon; Chlorophyll; Chromosome Mapping; Chromosomes; Climate; Communicable Diseases; Communities; Country; Data; Detection; Disease; Disease Outbreaks; Ecology; Elements; Environment; Environmental Risk Factor; Epidemic; Evolution; Food Supply; Frequencies; Gastroenteritis; Gene Transfer; Genes; Genetic; Genetic Recombination; Genetic Structures; Genetic Variation; Genotype; Health; Hospitalization; Human; Incidence; Individual; Infection; Inflammatory; Investigation; Investments; Knowledge; Lead; Learning; Left; Light; Link; Location; Minority; Modeling; Molecular; Molecular Genetics; Monitor; New Hampshire; Nitrogen; Organism; Oxygen; Oysters; Pathogenicity; Phenotype; Phosphorus; Population; Population Dynamics; Population Genetics; Prevalence; Protocols documentation; Publishing; Recording of previous events; Relative (related person); Research; Research Personnel; Risk; Scheme; Seasons; Shellfish; Site; Solid; Source; Structure; Study models; Temperature; Testing; Time; Vibrio; Vibrio parahaemolyticus; Virulence; Virulent; Water; Wound Infection; base; climate change; coastal water; cytotoxic; cytotoxicity; environmental change; experience; foodborne illness; insight; land use; pandemic disease; pathogen; predictive modeling; prevent; programs; public health relevance; stem; trait; warm temperature

DESCRIPTION (provided by applicant): Numerous infectious diseases are caused by minority strains within otherwise nonpathogenic species, but the ecological and population genetic mechanisms that drive their emergence remains unclear. Understanding these dynamics is especially important in light of the increasing frequency of many epidemics tied to changes in climate and land use. For example, illness caused by contaminated shellfish is relatively infrequent in most of the U.S. but incidence is on the rise and beginning to parallel that of warmer countries. The abundance of the major causative bacterium Vibrio parahaemolyticus (Vp) is positively correlated with warmer waters with moderate salinity. Yet these ecological variables do not sufficiently predict Vp epidemics in part because the relative abundance of potentially pathogenic Vp is far less predictable. This project seeks to identify and quantify the ecological factors that influence the relative prevalence of virulent Vp in oysters. Our model study area, the Great Bay estuary of New Hampshire, is ideal because of the wide range of environmental conditions that occur over relatively small spatial scales, and because its warmer waters promote species typically associated with warmer climates. Vp are known to reside in this estuary along with other pathogenic Vibrios and there have been several acute Vp infections from the estuary suggesting that minority pathogenic strains are resident in the community. Our focal question is: how do environmental factors drive the population dynamics of Vp? We hypothesize that Vp strains that vary in virulence traits are associated with certain environmental variables, such that fluctuations in climate will specifically influence the relative abundance of virulent Vp. We base this hypothesis on our preliminary data that shows a significant correlation between the prevalence of highly cytotoxic strains and increased temperature. Using multi-locus sequence typing analysis (MLST), we will examine the population structure and extent of recombination between estuary isolates. Our preliminary genetic typing thus far suggests that there is significant genetic exchange within the community that has three distinct Vp populations. The proposed study is unique from those published, specifically by 1) the inclusion of the diverse natural population (not only a subset with specific virulence markers), 2) a genetic typing scheme that includes known and putative virulence genes and allows the detection of virulence gene transfer within the population, and 3) it includes a characterization of functional virulence that will be overlaid upon the molecular typing scheme. We have two specific aims that address the following questions: Do environmental factors influence the virulence potential of natural Vp populations in oysters? What is the genetic structure of northern Vp populations and how are pathogenic elements linked to this structure? PUBLIC HEALTH RELEVANCE: Recent major outbreaks of Vibrio parahaemolyticus in cooler northern climes have been linked not to the pandemic clone, but to distinct resident bacteria of unique genetic composition, perhaps foreshadowing the increasing risk to human health due to global climate change. A major obstacle to assessing risk of infection and developing preventative protocols is a lack of understanding of what factors contribute to the emergence of virulent biovars within natural V. parahaemolyticus populations. The combined molecular typing and virulence assessment in the context of estuarine ecology will provide invaluable insight necessary to generate predictive models for this emerging pathogen.

描述（由申请人提供）：许多传染病是由其他非致病性物种中的少数族菌株引起的，但是驱动其出现的生态和种群遗传机制仍不清楚。鉴于与气候和土地使用变化相关的许多流行病的频率的增加尤其重要。例如，在美国大多数地区，受污染贝类引起的疾病相对很少见，但发病率正在上升并开始平行于温暖的国家。主要的致病细菌弧菌（VP）的丰度与中等盐度的温暖水呈正相关。然而，这些生态变量部分不能充分预测VP流行病，部分原因是潜在的致病VP的相对丰度要少得多。该项目旨在识别和量化影响牡蛎中有毒VP相对普遍存在的生态因素。我们的模型研究区域是新罕布什尔州的大湾河口，是理想的选择，因为在相对较小的空间尺度上发生的各种环境条件范围很广，并且由于其温暖的水域促进了通常与温暖气候相关的物种。众所周知，VP与其他致病性颤音一起居住在河口中，并且河口有几种急性VP感染，表明少数族裔致病菌株居住在社区中。我们的重点是：环境因素如何推动VP的人口动态？我们假设毒力性状不同的VP菌株与某些环境变量有关，因此气候波动将特别影响有毒VP的相对丰度。我们以初步数据为基础，该假设显示了高度细胞毒性菌株的患病率与温度升高之间的显着相关性。使用多层次序列分析分析（MLST），我们将检查河口分离株之间重组的种群结构和程度。迄今为止，我们的初步遗传分类表明，社区内有三个不同的VP人群的遗传交换。拟议的研究是独一无二的，特别是通过1）包含多样化的自然人口（不仅具有特定毒力标记的子集），2）一种遗传分类方案，其中包括已知和假定的毒力基因，并允许在人群中检测毒力基因转移，并且3）在功能性毒力的表征中会覆盖该方案。我们有两个具体的目标来解决以下问题：环境因素是否影响牡蛎中天然VP种群的毒力潜力？ 北部VP人群的遗传结构是什么？致病元素如何与该结构相关联？ 公共卫生相关性：最近在较冷的北部气体中发生的颤音溶血性的主要暴发与大流行克隆有关，而是与独特的遗传组成的独特居民细菌有关，也许预示着由于全球气候变化而导致人类健康风险的增加。评估感染风险和制定预防方案的主要障碍是缺乏了解哪些因素有助于自然V. parahaemolyticus种群中有毒生物群的出现。在河口生态学背景下的分子型和毒力评估的组合评估将为这种新兴病原体生成预测模型所需的宝贵见解。

项目成果

Genetic characterization of clinical and environmental Vibrio parahaemolyticus from the Northeast USA reveals emerging resident and non-indigenous pathogen lineages.

• DOI: 10.3389/fmicb.2015.00272
• 发表时间: 2015
• 期刊: Frontiers in microbiology
• 影响因子: 5.2
• 作者: Xu F;Ilyas S;Hall JA;Jones SH;Cooper VS;Whistler CA
• 通讯作者: Whistler CA

Sequence Type 631 Vibrio parahaemolyticus, an Emerging Foodborne Pathogen in North America.

• DOI: 10.1128/jcm.02162-16
• 发表时间: 2017-02
• 期刊: Journal of clinical microbiology
• 影响因子: 9.4
• 作者: Xu F;Gonzalez-Escalona N;Haendiges J;Myers RA;Ferguson J;Stiles T;Hickey E;Moore M;Hickey JM;Schillaci C;Mank L;DeRosia-Banick K;Matluk N;Robbins A;Sebra RP;Cooper VS;Jones SH;Whistler CA
• 通讯作者: Whistler CA