凡纳滨对虾细菌性病原的分离鉴定和耐药性研究

从5批患病的凡纳滨对虾分离细菌性病原,共分离纯化了50株细菌,随机选择形态差异的11株进行16S rDNA基因测序。测序结果表明,这11株菌主要分布在节杆菌属、弧菌属、芽胞杆菌属、微小杆菌属和希瓦氏菌属。对其中2株弧菌进行16S rDNA基因系统进化树分析,发现1株A1-1可能为Vibrio parahaemolyticus(副溶血性弧菌),而另外1株菌A2-3可能为Vibrio rotiferianus(半滑舌鳎病原菌轮虫弧菌)。形态和生理生化鉴定表明A1-1符合副溶血性弧菌的基本特征,可能是副溶血性弧菌中的一个型。人工感染实验表明A1-1对金鲫鱼具有明显的致病性,1×10~6 CFU感染剂量时能使80%金鲫鱼死亡。耐药性分析表明A1-1对土霉素、红霉素有较强的抗药性,而对链霉素、新霉素、四环素和氟本尼考均表现一定的敏感性。

Isolation, Identification and Drug Sensitivity Test of Bacterial Pathogen from Vanname Prawn (Litopenaeus vannamei)

50 bacterial strains were isolated and purified from five batches of sick vanname prawn （Litopenaeus vannamei）,and 11 strains with different morphs were randomly selected and identified by 16S rDNA sequence analysis.The result showed that the isolated strains belonged to the genus of Arthrobacter,Vibrio,Bacillus,Exiguobacterium,and Shewanella.Two Vibrio strains among them were analyzed with 16S rDNA phylogenetic tree,and found that strain A1-1 might be Vibrio parahaemolyticus,while strain A2-3 might be Vibrio rotiferianus.Morph and chemical and physiological characterization showed that A1-1 strain accorded with basic features of Vibrio parahaemolyticus and possibly be a type of Vibrio parahaemolyticus.Artificial infection experiments showed that A1-1 had remarkable pathogenicity against gold crucian carp,and infective dose at 1 × 106 CFU could cause 80％ of gold crucian carp to die.Bacteria A1-1 showed fairly strong resistance to oxytetracycline and erythromycin,and showed certain degree sensitivity to streptomycin,neomycin,tetracycline and florfenicol.