作为一种机会性病原体,Veronii气单胞菌可引起各种水生动物的出血性败血症。在我们目前的研究中,优势菌株SJ4,分离自自然感染的普通话鱼(Sinipercachuatsi),根据形态学鉴定为A.veronii,生理,和生化特征,以及分子鉴定。在Chuatsi中腹膜内注射维氏A.SJ4,显示出与自然感染相似的临床症状,SJ4在一周内的中位致死剂量(LD50)为3.8×105CFU/mL。组织病理学分析显示分离株SJ4可引起细胞增大,明显出血,和S.chuatsi的炎症反应。毒力基因的检测表明,分离株SJ4具有一定的作用,FIM,flgM,ompa,唇,hly,aer,和eprCAL,分离株SJ4也产生酪蛋白蛋白酶,dnase,明胶酶,和溶血素.此外,对维龙杆菌SJ4的完整基因组进行了测序,维龙杆菌SJ4的基因组大小为4562,694bp,在58.95%的G+C含量内,包含4079个编码基因。九百十种编码几种毒力因子的基因,如III型和VI型分泌系统,鞭毛,运动性,等。,基于VFDB数据库确定。此外,与四环素类药物相关的27个类别中的148个抗生素抗性相关基因,氟喹诺酮类药物,氨基糖苷类,大环内酯类,氯霉素,和头孢菌素也被注释。目前的结果表明,在这段时间内,维罗氏A是引起S.chuatsi细菌性败血症的病原体,为揭示维氏A的发病机制和耐药机制提供了有价值的基础。
As an opportunistic pathogen, Aeromonas veronii can cause hemorrhagic septicemia of various aquatic animals. In our present study, a dominant strain SJ4, isolated from naturally infected mandarin fish (Siniperca chuatsi), was identified as A. veronii according to the morphological, physiological, and biochemical features, as well as molecular identification. Intraperitoneal injection of A. veronii SJ4 into S. chuatsi revealed clinical signs similar to the natural infection, and the median lethal dosage (LD50) of the SJ4 to S. chuatsi in a week was 3.8 × 105 CFU/mL. Histopathological analysis revealed that the isolate SJ4 could cause cell enlargement, obvious hemorrhage, and inflammatory responses in S. chuatsi. Detection of virulence genes showed the isolate SJ4 carried act, fim, flgM, ompA, lip, hly, aer, and eprCAL, and the isolate SJ4 also produce caseinase, dnase, gelatinase, and hemolysin. In addition, the complete genome of A. veronii SJ4 was sequenced, and the size of the genome of A. veronii SJ4 was 4,562,694 bp, within a G + C content of 58.95%, containing 4079 coding genes. Nine hundred ten genes encoding for several virulence factors, such as type III and VI secretion systems, flagella, motility, etc., were determined based on the VFDB database. Besides, 148 antibiotic resistance-related genes in 27 categories related to tetracyclines, fluoroquinolones, aminoglycosides, macrolides, chloramphenicol, and cephalosporins were also annotated. The present results suggested that A. veronii was etiological agent causing the bacterial septicemia of S. chuatsi in this time, as well as provided a valuable base for revealing pathogenesis and resistance mechanism of A. veronii.