致病性假交替单胞菌的分离鉴定及药敏特性研究

Isolation and Identification of Pathogenic Pseudoalteromonas sp. and Antibiotic Sensitivity Research

[目的]分离鉴定患病的七带石斑鱼(Epinephelus septemfasciatus Thunberg)的致病菌,并研究其药敏特性。[方法]从患病的七带石斑鱼体内分离出1株致病菌BY0081。通过ATB微生物鉴定系统和菌体常规形态特征、生理生化反应指标测定以及16S rDNA测序分析等进行综合鉴定;通过人工感染水生模式动物剑尾鱼测定该菌株对其的半数致死量(LD50);最后进行药敏试验确定其药敏特性。[结果]致病菌BY0081为革兰氏阴性菌,菌落呈米色,边缘光滑,中间略有隆起,为假交替单胞菌(Pseudoa lteromonas sp.)。其在较低的温度下仍有较强的毒力,其对水生模式动物剑尾鱼(Xiphophorus helleri)的LD50为2.82×105cfu/g鱼体重。该菌对菌必治、复方新诺明、氯霉素和氟哌酸等抗生素高度敏感,对复达欣、红霉素、丁胺卡那霉素和庆大霉素等药物中度敏感。[结论]该研究对防治由假交替单胞菌引起的鱼类疾病有积极意义。

[Objective] The research aimed to isolate and identify the pathogenic bacterial strain from diseased Epinephelus septemfasciatus,and study its antibiotic sensitivity.[Method] A pathogenic bacterial strain BY0081 was isolated from diseased EpinepheLus septemfasciatus.The ATB system,traditional physiological and biochemical experiments and 16S rDNA gene homology comparison of the bacteria were used to identify it.The infecting experiment of Xiphophorus helleri was used to determine LD50.Then its antibiotic sensitivity was studied.[Result] Strain BY0081 was gram negative and the colony,the edge of which was lubricity,beige.The isolated strain BY0081 belonged to Pseudoalteromonas sp..In the Low temperature condition,it could also have strong pathogenicity.The LD50 of the strain BY0081 to Xiphophorus helleri was 2.82×105cfu/g.In addition,strain BY0081 was highly sensitive to Choramphenicol,Ceftriaxone,Sinomin,Norfloxacin and intermediately sensitive to eight kinds of antibiotics including Fortum,Erythromycin,Ofloxacin,Ceftazidime,Ciprofloracin,Amikacin,Minocycline hydrochloride hydrate,Gentamycin.[Conclusion] The study has positive meaning to defend and control fish diseases caused by Pseudoalteromonas sp..