Evolutionary Model of Cluster Divergence of the Emergent Marine Pathogen Vibrio vulnificus: From Genotype to Ecotype
Evolutionary Model of Cluster Divergence of the Emergent Marine Pathogen Vibrio vulnificus: From Genotype to Ecotype
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DOI：
10.1128/mbio.02852-18
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发表时间：
2019-01-01
期刊：
影响因子：
6.4
通讯作者：
Almagro-Moreno, Salvador
中科院分区：
文献类型：
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作者：
Lopez-Perez, Mario;Jayakumar, Jane M.;Almagro-Moreno, Salvador
创伤弧菌是一种机会致病菌，是一种危及生命的败血症的病原体，也是世界范围内水产养殖业日益严重的问题。区分其临床和环境菌株的遗传因素仍然是个谜。此外，临床菌株已经出现在创伤弧菌的每个进化枝中。在这项工作中，我们从进化和生态学的角度研究了创伤弧菌的基因组特性和种群动态。113株创伤弧菌分离株的基因组比较和生物信息学分析表明，创伤弧菌种群由4个不同的簇组成。我们发现的证据表明，两个最大的集群（集群1 [C1]和C2）之间的重组和基因流已经急剧减少到它们独立发散的程度。泛基因组和表型分析显示，这两个集群有两种明显不同的生活方式，表明拟南芥（C2）和布卢默（C1）的生态类型，在碳水化合物利用，防御系统和趋化性，以及其他特征的差异。尽管如此，我们还是发现了移动的遗传因子在物种内和物种间的频繁交换（例如，抗生素抗性质粒、新的“染色质”或两种不同且同时存在的VI型分泌系统），其在群体中提供高水平的遗传多样性。令人惊讶的是，我们在水产养殖物种的粘膜中鉴定了来自这两个集群的菌株，这表明人造生态位将来自这两个集群的菌株带到了一起。我们提出了一个创伤弧菌的进化模型，可以广泛适用于其他致病性弧菌和兼性细菌病原体，以寻求战略，以防止其感染和emergency.IMPORTANCE创伤弧菌是一种新兴的海洋病原体，是致命的败血症的原因。然而，区分其临床和环境菌株及其几种生物型的遗传因素仍然是谜。在这项工作中，我们研究了创伤弧菌的潜在基因组特性和种群动态，以阐明使这些菌株成为人类病原体的特征。获得不同的生态决定因素可能会使在同一环境中发展出具有不同生活方式的高度分化的集群。然而，我们在水产养殖物种的粘膜中鉴定了来自这两个集群的菌株，这表明人为的生态位将来自这两个集群的菌株带到了一起，造成了重组和出现新变体的潜在风险。我们提出了一个新的进化模型，提供了一个视角，可以广泛适用于其他致病性弧菌和兼性细菌病原体，以寻求预防感染的策略。
Vibrio vulnificus, an opportunistic pathogen, is the causative agent of a life-threatening septicemia and a rising problem for aquaculture worldwide. The genetic factors that differentiate its clinical and environmental strains remain enigmatic. Furthermore, clinical strains have emerged from every clade of V. vulnificus. In this work, we investigated the underlying genomic properties and population dynamics of the V. vulnificus species from an evolutionary and ecological point of view. Genome comparisons and bioinformatic analyses of 113 V. vulnificus isolates indicate that the population of V. vulnificus is made up of four different clusters. We found evidence that recombination and gene flow between the two largest clusters (cluster 1 [C1] and C2) have drastically decreased to the point where they are diverging independently. Pangenome and phenotypic analyses showed two markedly different lifestyles for these two clusters, indicating commensal (C2) and bloomer (C1) ecotypes, with differences in carbohydrate utilization, defense systems, and chemotaxis, among other characteristics. Nonetheless, we identified frequent intra- and interspecies exchange of mobile genetic elements (e.g., antibiotic resistance plasmids, novel "chromids," or two different and concurrent type VI secretion systems) that provide high levels of genetic diversity in the population. Surprisingly, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together. We propose an evolutionary model of V. vulnificus that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections and emergence.IMPORTANCE Vibrio vulnificus is an emergent marine pathogen and is the cause of a deadly septicemia. However, the genetic factors that differentiate its clinical and environmental strains and its several biotypes remain mostly enigmatic. In this work, we investigated the underlying genomic properties and population dynamics of the V. vulnificus species to elucidate the traits that make these strains emerge as a human pathogen. The acquisition of different ecological determinants could have allowed the development of highly divergent clusters with different lifestyles within the same environment. However, we identified strains from both clusters in the mucosa of aquaculture species, indicating that manmade niches are bringing strains from the two clusters together, posing a potential risk of recombination and of emergence of novel variants. We propose a new evolutionary model that provides a perspective that could be broadly applicable to other pathogenic vibrios and facultative bacterial pathogens to pursue strategies to prevent their infections.