南美白对虾霍乱弧菌的分离与鉴定研究

Isolation and identification of Vibrio cholera from Penaeus vannamei

目前南美白对虾(Penae usvannamei)人工养殖中,病害多发,本研究从一养殖场中采集发病病虾,从患病对虾肝胰腺中分离病原菌.对分离菌株进行形态观察,生理生化测定并结合16SrDNA序列分析进行鉴定,结果表明,该分离菌为霍乱弧菌(Vibrio cholera),回归感染证明其为致病菌,可导致南美白对虾死亡.通过纸片琼脂扩散法对32种抗生素进行药物敏感试验,病原菌对氟苯尼考、氯霉素、利福平、诺氟沙星等10种抗生素敏感,对头孢呋辛、头孢曲松等7种药物中度敏感,对羧苄西林、青霉素等15种药物具有抗性.通过二倍稀释法测定筛选5种常用抗生素最小抑菌浓度,结果表明诺氟沙星抑菌效果最强,最小抑菌浓度最小<0.2441μg/mL.

Recently, diseases seriously outbreak in Penaeus vannamei of artificial breeding. In this study, the infected Penaeus vannamei were collected from one aquaculture farm and the pathogen was isolated from hepatopancreas. The isolated pathogen was identified via morphological observation, physiological and biochemical characters and 16S rDNA sequence analysis. The results showed that, the isolated bacterium was identified as Vibrio cholera . The regression experiment also demonstrated it was the pathogen which caused the death of the shrimp. The drug sensitive test of 32 antibiotics was detected using K-B way, the results showed that V. cholerae was highly sensitive to 10 antibiotics including florfenicol, chloramphenicol, rifampicin, norfloxacin, etc;intermediate sensitive to 7 antibiotics including cefuroxime, ceftriaxone, etc;resistant to 15 antibiotics including carboxy ampicillin, penicillin, etc. The minimum inhibitory concentration (MIC) of 5 selected antibiotics was also detected using tube double dilution method, norfloxacin showed the best inhibiting effect and the value was less than 0.244 1 μg/mL.