anguillarum弧菌是海水养殖中重要的鱼类病原体,这可能会感染鱼类,造成巨大的经济损失。在这项研究中,从sebastesschlegelii分离出的A弧菌被命名为VA1,并从形态学方面进行了鉴定和表征,生理生化特性,16SRNA,毒力基因,药物敏感性,和胞外酶活性。同时,在基因组水平研究VA1。结果表明,从患病的鱼中分离出革兰氏阴性。VA1的特征是表面不均匀,可见鞭毛包裹在鞘和微泡结构中。根据16SRNA序列和生理生化特性,将VA1鉴定为anguillarum。VA1携带大部分毒力基因(24/29),对青霉素具有抗性,苯唑西林,氨苄青霉素,头孢拉定,新霉素,吡哌酸,氧氟沙星,和诺氟沙星.通过实验分析证实了分离菌株的致病性,LD50为6.43×106CFU/ml。VA1具有分泌明胶酶的能力,蛋白酶,和淀粉酶,它有α溶血。VA1的全基因组大小为4232328bp,G+C含量为44.95%,由两个环状染色体组成,染色体1和染色体2,无质粒。有1006个预测的蛋白质编码序列(CDS)。共有526个基因被预测为毒力相关基因,可归类为IV型菌毛,鞭毛,溶血素,铁载体,和VI型分泌系统。受影响器官和组织的组织病理学检查支持了毒力基因和相关数据。194个基因被预测为抗生素抗性基因,包括氟喹诺酮类抗生素,氨基糖苷类抗生素,和β-内酰胺抗性基因,与上述药物敏感性的结果一致,表明VA1是一种多重耐药细菌。本研究为更好地理解致病性和抗生素耐药性提供了理论依据,这可能有助于将来预防anguillarum。
Vibrio anguillarum is an important fish pathogen in mariculture, which can infect fish with great economic losses. In this study, a Vibrio anguillarum isolated from Sebastes schlegelii was named VA1 and was identified and characterized from aspects of morphology, physiological and biochemical characteristics, 16SRNA, virulence genes, drug sensitivity, and extracellular enzyme activity. At the same time, The VA1 was investigated at the genomic level. The results showed that a Gram-negative was isolated from the diseased fish. The VA1 was characterized with uneven surface and visible flagella wrapped in a sheath and microbubble structures. The VA1 was identified as Vibrio anguillarum based on the 16S RNA sequence and physiological and biochemical characteristics. The VA1 carried most of the virulence genes (24/29) and was resistant to penicillin, oxacillin, ampicillin, cefradine, neomycin, pipemidic acid, ofloxacin, and norfloxacin. The pathogenicity of the isolated strain was confirmed by an experimental analysis, and its LD50 was 6.43 × 106 CFU/ml. The VA1 had the ability to secrete gelatinase, protease, and amylase, and it had α-hemolysis. The whole genome size of the VA1 was 4232328bp and the G + C content was 44.95 %, consisting of two circular chromosomes, Chromosome1 and Chromosome2, with no plasmid. There were 1006 predicted protein coding sequences (CDSs). A total of 526 genes were predicted as virulence-related genes which could be classified as type IV pili, flagella, hemolysin, siderophore, and type VI secretion system. Virulence genes and correlation data were supported with the histopathological examination of the affected organs and tissues. 194 genes were predicted as antibiotic resistance genes, including fluoroquinolone antibiotic, aminoglycoside antibiotic, and beta-lactam resistant genes, which agreed with the results of the above drug sensitivity, indicating VA1 to be a multidrug-resistant bacterium. This study provided a theoretical basis for a better understanding of pathogenicity and antibiotic resistance, which might contribute to the prevention of V. anguillarum in the future.