Vibrio parahaemolyticus is becoming the leading cause of acute bacterial gastroenteritis, but its population dynamics in aquafarms have received limited attention. To address this research gap, we selected three shellfish farms to examine the impacts of ocean currents and the transport of live aquatic animals on the transmission and microevolution of V. parahaemolyticus by using multilocus sequence typing (MLST) and whole-genome sequencing. MLST and genomic analysis revealed that the community structure of V. parahaemolyticus in Dalian and Donggang was relatively stable in the presence of ocean currents; however, horizontal gene transfer of mobile genetic elements (MGEs) between Dalian and Donggang was very common. Further analysis indicated that the transport of live aquatic animals from Dalian to Xiamen not only introduced new V. parahaemolyticus populations but also allowed the exchange of genetic material between the two sites. More interestingly, Dalian-originated strain ST722 was introduced to Xiamen farms, resulting in one MLST allele change and the acquisition of two genomic islands from indigenous isolates in Xiamen within 8 months; such alterations are thought to promote the adaptation of V. parahaemolyticus. These results provide direct observations of how ocean currents and the transport of live aquatic animals contribute to the dissemination and genetic mixture of V. parahaemolyticus, which provides insights into the dynamics and microevolution of V. parahaemolyticus in aquacultural environments.

中文翻译：

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贝类养殖场副溶血性弧菌种群的动态和微进化

副溶血性弧菌正在成为急性细菌性肠胃炎的主要原因，但其在水产养殖场中的种群动态受到的关注有限。为了弥补这一研究空白，我们选择了三个贝类养殖场，以利用多基因座序列分型（MLST）和全基因组测序研究洋流和活水生动物的运输对副溶血弧菌的传播和微进化的影响。MLST和基因组分析表明副溶血弧菌的群落结构在洋流的影响下，大连和东港的相对稳定。然而，大连和东港之间的移动遗传元件（MGE）的水平基因转移非常普遍。进一步的分析表明，从大连到厦门的活水生动物运输不仅引入了新的副溶血弧菌种群，而且还允许两个地点之间交换遗传物质。更有趣的是，源自大连的ST722菌株被引入厦门养殖场，导致一个MLST等位基因发生变化，并在8个月内从厦门的本地分离物中获得了两个基因岛。这种改变被认为可以促进副溶血弧菌的适应。。这些结果直接观察了洋流和活水生动物的运输如何促进副溶血弧菌的传播和遗传混合物，从而提供了对水产养殖环境中副溶血弧菌的动力学和微进化的见解。