Evidence of Environmental Evolution of Toxigenic Vibrio cholerae in Aquatic Reservoirs

Persistent aquatic environmental reservoirs for Vibrio cholerae are present in Asia; however, their existence in other parts of the world remains controversial. The single-source introduction of V. cholerae O1 in Haiti, in the aftermath of the 2010 earthquake, provided a unique opportunity to determine the role aquatic reservoirs play in seasonal outbreaks. Whole genome sequence Bayesian phylogeography showed robust evidence of V. cholerae O1 persistence-driven evolution in the aquatic environment through the establishment of reservoirs during lull periods of the Haitian epidemic. Novel lineages emerged in the environment from sequential population bottlenecks, characterized by mutations in genes potentially involved in adaptive response. The data highlight the importance of the aquatic environment in overall persistence and evolution of this global pathogen.

霍乱弧菌（Vibrio cholerae）的持久性水生环境储库在亚洲广泛存在，但其在全球其他地区的存在性仍存争议。2010年海地地震后，当地发生的O1群霍乱弧菌单源输入事件，为明确水生储库在季节性暴发中的作用提供了独一无二的研究契机。全基因组序列贝叶斯系统地理学分析显示，在海地疫情的间歇期，霍乱弧菌O1群通过建立水生储库，在水环境中发生了由持续性定植驱动的进化，该结论得到了确凿证据的支撑。在经历连续的种群瓶颈事件后，水环境中诞生了新的进化谱系，这些谱系的特征为携带了可能与适应性应答相关的基因突变。本研究数据凸显了水环境在这一全球性病原菌的持续存活与整体进化过程中的重要作用。