海南罗非鱼致病性维氏气单胞菌分离鉴定及药敏特性研究

摘要

There was an outbreak mortality of tilapia (Oreochromis niloticus) in several farms of Hainan province from the March to May ,2014 .Twelve dominant bacterial strains were isolated from diseased tila‐pia using routine bacterial isolation method .Artificial challenge test showed that the isolated strains HN‐G‐03 and HN‐B‐02 from the liver and brain of moribund tilapia possessed strong virulence ,the LD50 of the two strains to healthy tilapia by intraperitoneal injection challenge were 7 .12 × 105 cfu/fish and 1 .32 × 105 cfu/fish ,respectively .Based on the results of 16S rRNA and gryB gene sequence analysis ,morphological observation ,and physiological and biochemical characteristic analysis ,HN‐G‐03 was identified as Aero‐monas veronii bv . veronii and HN‐B‐02 was A . veronii bv . sobria . The antibiotic sensitivity analysis showed that both HN‐G‐03 and HN‐B‐02 were resistant to 12 kinds of drugs including penicillin ,furazoli‐done ,ampicillin ,spectinomycin ,cefuroxim ,and streptomycin ,only sensitive to levofloxacin ,doxycyc‐line ,florfenicol ,enrofloxacin and gentamicin .The findings provided a further scientific basis for the pre‐vention and treatment of tilapia diseases .%2014年3—5月海南省罗非鱼主养区多个养殖场发生爆发性疾病，从患病尼罗罗非鱼不同组织中分离获得12株优势菌。经人工回归感染试验，从肝脏和脑中分离获得的H N‐G‐03和H N‐B‐02菌株具较强的致病力，H N‐G‐03和 H N‐B‐02菌株对罗非鱼的的半致死密度分别为7．12×105 cf u／尾和1.32×105 cfu／尾。经16S rRNA和gyrB基因序列分析，同时结合细菌的形态学特征、生理生化特征，菌株H N‐G‐03和H N‐B‐02分别被鉴定为维氏气单胞菌的维氏生物型和温和生物型。体外药物药敏试验结果显示，两株菌均对左氧氟沙星、强力霉素、氟苯尼考、恩诺沙星、庆大霉素等5种药物高度敏感，对呋喃妥因等3种药物中度敏感，对青霉素等12种药物较强耐药。