西伯利亚鲟致病性嗜水气单胞菌的分离鉴定

摘要

为分离鉴定引起四川省绵阳市水箱养殖的西伯利亚鲟患病及死亡的病原菌,本研究从患病西伯利亚鲟脾脏组织分离纯化得到一株病原菌,命名为XYCY-1.对其进行了形态特征、理化特性等生物学表型检验、感染回归试验、16S rRNA基因进化分析、病理观察及药敏试验.结果显示,该菌属于嗜水气单胞菌;人工感染试验显示该分离菌对西伯利亚鲟鱼具有致病性,实验鱼发病和死亡症状与自然发病鱼基本相同.表明嗜水气单胞菌是此次鲟鱼发病的病原;分离菌株对头孢西丁、卡那霉素、庆大霉素、强力霉素、氧氟沙星、恩诺沙星、新霉素7种药物敏感,对氨苄青霉素、四环素、洛美沙星等13种药物耐药.本研究对四川绵阳地区鲟鱼发病流行的病因作出了准确诊断,为该地区鱼病预防和合理用药提供了依据.%In order to identify the pathogen caused a severe disease in farmed fish in Mianyang district of Sichuan,a dominant bacteria,named XYCY-1,was isolated from the spleen of diseased Siberian sturgeons (Acipenser Baerii).It was together confirmed to be Aeromonas hydrophila on the basis of the morphology,physiological and biochemical characteristics,the phylogenetic analysis of 16S rRNA gene.By artificial infection,the XYCY-1 was found to be pathogenic to Siberian sturgeons.The symptoms caused by XYCY-1 to the experimental fish were consistent with those of the natural disease,suggesting the epidemic disease was caused by this pathogen.The antibiotic sensitivity test demonstrated that XYCY-1 was sensitive to 7 antibiotics,including Cefoxitin,Kanamycin,Gentamycin,Doxycycline,Ofloxacin,Enoxacin,Novobiocin,and was intermediately sensitive to Ampicillin,Tetracycline but resist to 13 antibiotic such as Amphotericin B,Sulfamethoxazole ect.This study has made an accurate diagnosis for the cause of the epidemic of sturgeon in Mianyang,Sichuan and provides the basis for preventing and controlling the fish disease caused by Aeromonas hydrophila in this region.