半滑舌鳎体表溃疡病病原的分离鉴定

Isolation and Identification of the Pathogens of the Skin Ulceration Disease of Cynoglossus semilaevis

为研究引起半滑舌鳎(Cynoglossus semilaevis)体表溃疡病的病原,从发生体表溃疡的半滑舌鳎体表病灶、肝脏和肾脏上进行细菌分离,得到2株优势菌株051001和051002,采用腹腔注射进行回感实验,证实菌株051001和051002能够引起养殖半滑舌鳎发病死亡,该菌株为本次半滑舌鳎体表溃疡病的致病菌。经形态学观察和生理生化特性分析,初步判定菌株051001为鱼肠道弧菌(Vibrio ichthyoenteri)、菌株051002为哈维氏弧菌(Vibrio harveyi);基于16SrRNA基因构建的系统发育树显示,菌株051002与哈维氏弧菌聚为一支,菌株051001与鱼肠道弧菌聚为一个分支;基于hsp60的基因序列分析表明051002与哈维氏弧菌(AY332570、AF230931)聚为一个分支,置信度为92%。对16种药物的敏感实验证实,菌株051001对利福平、庆大霉素、氟苯尼考等敏感,菌株051002对诺氟沙星、头孢曲松钠、庆大霉素敏感。

The aims of this research were to isolate the pathogens of the skin ulceration disease of Cynoglossus semilaevis and to identify the sensitivity to antibiotics.Two dominant bacterial strains documented as 051001 and 051002were isolated from the skin,liver and kidney of dying C.semilaevis.Both strains could cause the mortality of healthy C.semilaevisindependently in artificially challenge and were proved to be pathogens of C.semilaevis.Based on the results of morphological observation,physiological and biochemical characterization and 16 S rRNA gene sequence,strain 051001 was identified as Vibrioichthyoenteriand strain 051002 was V.harveyi.Phylogenetic tree of Vibrio based on hsp60 gene indicated that strain 051002 showed the highest level of similarity to V.harveyi,and the bootstrap was92%.Antibiotic sensitivity analysis showed that strain 051001 was susceptible to rifampicine,florfenicol,furazolidone,gentamicinum and streptomycin;while strain 051002 was susceptible to norfloxacin,rocephin and gentamicinum.