Sullivan Roisin, Becker Joy A, Zadoks Ruth N, Venturini Carola, Esteves Ana I S, Benedict Suresh, Fornarino Dani L, Andrews Hannah, Okoh God'spower R, Bhardwaj Vidya, Sistrom Mark, Westman Mark E, Phuoc Nguyen Ngoc, Samsing Francisca
Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia.
School of Life and Environmental Sciences, Faculty of Science, The University of Sydney, Camden, New South Wales, Australia.
PLoS One. 2025 May 19;20(5):e0319450. doi: 10.1371/journal.pone.0319450. eCollection 2025.
Vibrio species are an emerging public and animal health risk in marine environments and the opportunistic bacterial pathogen Vibrio harveyi is a major disease risk for tropical aquaculture. Current understanding of virulence in V. harveyi is limited by strain-specific variability and complex host-pathogen dynamics. This study sought to integrate genomic investigation, phenotypic characterisation and in vivo challenge trials in barramundi (Lates calcarifer) to increase our understanding of V. harveyi virulence. We identified two hypervirulent isolates, Vh-14 and Vh-15 that caused 100% mortality in fish within 48 hours, and that were phenotypically and genotypically distinct from other V. harveyi isolates. Virulent isolates contained multiple plasmids, including a 105,412 bp conjugative plasmid with type III secretion system genes originally identified in Yersinia pestis. The emergence of this hypervirulent plasmid-mediated patho-variant poses a potential threat to the sustainable production of marine finfish in Southeast Asia, the Mediterranean and Australia. In addition, we observed an effect of temperature on phenotypic indicators of virulence with an increase in activity at 28°C and 34°C compared to 22°C. This suggests that temperature fluctuations associated with climate change may act as a stressor on bacteria, increasing virulence gene secretion and host adaptation. Our results utilising a myriad of technologies and tools, highlights the importance of a holistic view to virulence characterisation.
弧菌属细菌在海洋环境中对公众健康和动物健康构成了新出现的风险，而机会性病原菌哈维氏弧菌是热带水产养殖中的主要疾病风险因素。目前对哈维氏弧菌毒力的理解受到菌株特异性变异性和复杂的宿主-病原体动态关系的限制。本研究旨在整合基因组调查、表型特征分析以及在尖吻鲈（尖吻鲈）体内进行的攻毒试验，以增进我们对哈维氏弧菌毒力的理解。我们鉴定出了两株高毒力分离株，Vh - 14和Vh - 15，它们在48小时内导致鱼类100%死亡，并且在表型和基因型上与其他哈维氏弧菌分离株不同。有毒力的分离株含有多个质粒，包括一个105,412 bp的接合性质粒，其带有最初在鼠疫耶尔森菌中鉴定出的III型分泌系统基因。这种高毒力质粒介导的致病变体的出现对东南亚、地中海和澳大利亚的海洋硬骨鱼可持续生产构成了潜在威胁。此外，我们观察到温度对毒力表型指标有影响，与22°C相比，在28°C和34°C时活性增加。这表明与气候变化相关的温度波动可能对细菌起到应激源的作用，增加毒力基因的分泌和宿主适应性。我们利用多种技术和工具得出的结果凸显了对毒力特征进行整体观研究的重要性。
