Abdel-Glil Mostafa Y, Fischer Uwe, Steinhagen Dieter, McCarthy Una, Neubauer Heinrich, Sprague Lisa D
Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses (IBIZ), Jena, Germany.
Friedrich-Loeffler-Institut, Institute of Infectiology, Greifswald-Insel Riems, Germany.
Front Microbiol. 2021 Nov 18;12:782415. doi: 10.3389/fmicb.2021.782415. eCollection 2021.
is the causative agent of enteric redmouth disease (ERM), a serious infection that affects global aquaculture with high economic impact. The present study used whole genome sequences to perform a comparative analysis on 10 strains and to explore their genetic relatedness to other members of the genus. , , and formed a species complex that constitutes the most basal lineage of the genus. The results showed that the taxonomy of strains is better defined by using a core genome alignment and phylogenetic analysis. The distribution of accessory genes in all species revealed the presence of 303 distinctive genes in . Of these, 169 genes were distributed in 17 genomic islands potentially involved in the pathogenesis of ERM via (1) encoding virulence factors such as Afp18, Yrp1, phage proteins and (2) improving the metabolic capabilities by enhancing utilization and metabolism of iron, amino acids (specifically, arginine and histidine), and carbohydrates. The genome of is highly conserved regarding gene structure, gene layout and functional categorization of genes. It contains various components of mobile genetic elements but lacks the CRISPR- system and possesses a stable set of virulence genes possibly playing a critical role in pathogenicity. Distinct virulence plasmids were exclusively restricted to a specific clonal group of (CG4), possibly indicating a selective advantage. Phylogenetic analysis of genomes revealed the co-presence of multiple genetically distant lineages of strains circulating in Germany. Our results also suggest a possible dissemination of a specific group of strains in the United States, Peru, Germany, and Denmark. In conclusion, this study provides new insights into the taxonomy and evolution of and contributes to a better understanding of the pathogenicity of ERM in aquaculture. The genomic analysis presented here offers a framework for the development of more efficient control strategies for this pathogen.
是肠红嘴病（ERM）的病原体，这是一种严重感染，对全球水产养殖产生重大经济影响。本研究使用全基因组序列对10个菌株进行比较分析，并探索它们与该属其他成员的遗传相关性。 、 和 形成了一个物种复合体，构成了该属最基部的谱系。结果表明，使用核心基因组比对和系统发育分析能更好地定义菌株的分类。所有物种中辅助基因的分布显示在 中有303个独特基因。其中，169个基因分布在17个基因组岛中，可能通过以下方式参与ERM的发病机制：（1）编码毒力因子，如Afp18、Yrp1、噬菌体蛋白；（2）通过增强铁、氨基酸（特别是精氨酸和组氨酸）和碳水化合物的利用和代谢来提高代谢能力。 的基因组在基因结构、基因布局和基因功能分类方面高度保守。它包含各种移动遗传元件成分，但缺乏CRISPR -系统，并且拥有一组可能在致病性中起关键作用的稳定毒力基因。独特的毒力质粒仅局限于 的一个特定克隆群（CG4），这可能表明具有选择优势。对 基因组的系统发育分析揭示了在德国流行的 菌株中多个遗传距离较远的谱系共存。我们的结果还表明，特定菌株群可能在美国、秘鲁、德国和丹麦传播。总之，本研究为 的分类和进化提供了新见解，并有助于更好地理解ERM在水产养殖中的致病性。这里呈现的基因组分析为开发针对该病原体的更有效控制策略提供了框架。
