De Luca Eliana, Álvarez-Narváez Sonsiray, Maboni Grazieli, Baptista Rodrigo P, Nemeth Nicole M, Niedringhaus Kevin D, Ladner Jason T, Lorch Jeffrey M, Koroleva Galina, Lovett Sean, Palacios Gustavo F, Sanchez Susan
Athens Veterinary Diagnostic Laboratory, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.
Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.
Front Microbiol. 2021 Nov 22;12:667356. doi: 10.3389/fmicb.2021.667356. eCollection 2021.
The family has been associated with fatal diseases in numerous avian species. Several new taxa within this family, including Bisgaard taxon 40, have been recently described in wild birds, but their genomic characteristics and pathogenicity are not well understood. We isolated Bisgaard taxon 40 from four species of seabirds, including one sampled during a mass, multi-species mortality event in Florida, United States. Here, we present a comprehensive phenotypic and genetic characterization of Bisgaard taxon 40 and comparative genomic analysis with reference strains from the family, aiming at determining its phylogenetic position, antimicrobial susceptibility profile, and identifying putative virulence factors. multilocus sequence-based and whole-genome-based phylogenetic analysis clustered all Bisgaard taxon 40 strains together on a distinct branch separated from the other members of the family, indicating that Bisgaard taxon 40 could represent a new genus. These findings were further supported by protein similarity analyses using the concatenation of 31 conserved proteins and other taxonomic approaches such as the percentage of conserved protein test. Additionally, several putative virulence factors were identified, including those associated with adhesion (capsule, , ) and colonization (, , , , , , and ) of the host and a cytolethal distending toxin (), which may have played a role in disease development leading to the mortality event. Considerably low minimum inhibitory concentrations (MICs) were found for all the drugs tested, in concordance with the absence of antimicrobial resistance genes in these genomes. The novel findings of this study highlight genomic and phenotypic characteristics of this bacterium, providing insights into genome evolution and pathogenicity. We propose a reclassification of these organisms within the family, designated as gen. nov., with sp. nov. as the type species. The type strain is A25201 (=DSM 112696).
该家族与众多禽类的致命疾病有关。最近在野生鸟类中描述了该家族内的几个新分类单元，包括比斯加德分类单元40，但它们的基因组特征和致病性尚不清楚。我们从四种海鸟中分离出比斯加德分类单元40，其中一种是在美国佛罗里达州一次大规模多物种死亡事件中采集的。在此，我们对比斯加德分类单元40进行了全面的表型和遗传特征分析，并与该家族的参考菌株进行了比较基因组分析，旨在确定其系统发育位置、抗菌药物敏感性谱，并鉴定潜在的毒力因子。基于多位点序列和全基因组的系统发育分析将所有比斯加德分类单元40菌株聚集在一个与该家族其他成员分离的独特分支上，表明比斯加德分类单元40可能代表一个新属。使用31种保守蛋白的串联进行的蛋白质相似性分析以及其他分类方法（如保守蛋白测试百分比）进一步支持了这些发现。此外，还鉴定了几种潜在的毒力因子，包括与宿主黏附（荚膜、 、 ）和定植（ 、 、 、 、 、 、 ）相关的因子以及一种细胞致死性扩张毒素（ ），这些可能在导致死亡事件的疾病发展中起作用。在所测试的所有药物中均发现最低抑菌浓度（MIC）相当低，这与这些基因组中不存在抗菌抗性基因一致。本研究的新发现突出了这种细菌的基因组和表型特征，为基因组进化和致病性提供了见解。我们建议在该家族内对这些生物进行重新分类，指定为 属新种，其中 种新种为模式种。模式菌株为 A25201（=DSM 112696）。
