黄颡鱼致病性迟钝爱德华氏菌的分离、鉴定及特征分析  

Isolation,identification and characterization of Edwardsiella tarda from diseased Pelteobagrus fulvidraco

作　　者：胡兵 HU Bing(Fujian Province Key Laboratory of Special Aquatic Formula Feed,Fuqing 350308,China;Fujian Tianma Science and Technology Group Co.,LTD.Fuqing 350308,China)

机构地区：[1]福建省特种水产配方饲料重点实验室,福建福清350308 [2]福建天马科技集团股份有限公司,福建福清350308

出　　处：《武汉轻工大学学报》2022年第4期8-15,共8页Journal of Wuhan Polytechnic University

基　　金：福建省特种水产配合饲料重点实验室开放课题(TMKJZ1912).

摘　　要：2020年5月湖北太湖港街道某养殖场的黄颡鱼出现大量死亡现象,典型临床症状表现为鱼体头部出现“头穿孔”。为确定此次黄颡鱼的患病原因,从具有以上临床症状的病鱼组织中分离获得一株革兰氏阴性短杆菌,编号为EDT202005。采用形态学观察、生理生化鉴定、16S rRNA基因序列分析等技术鉴定该菌株为迟钝爱德华氏菌。药敏试验结果表明该菌株对水产常用抗生素盐酸多西环素和氟苯尼考耐药,但对恩诺沙星敏感。人工回归感染结果显示菌株可使黄颡鱼出现与自然发病鱼相似的症状,其对黄颡鱼的半致死浓度为2.51×10^(5) CFU/mL。石蜡切片显示该菌对感染鱼的鳃、脑、肠、肝、脾和肾组织均可造成损伤,呈全身性感染。试验确认了引起此次黄颡鱼“裂头病”的病原,并初步研究了迟钝爱德华氏菌的致病性以及药物敏感性,试验结果将为黄颡鱼“裂头病”的有效防控提供科学指导。In May 2020,a large amount of Pelteobagrus fulvidraco with typical clinical symptoms of head perforation cultured in Taihugang streat,Hubei province,was found death.A gram-negative bacterium,deemed as EDT202005,was isolated from the diseased fish.The isolate strain was identified as Edwardsiella tarda by its morphological,physiological,and biochemical features,as well as 16S rRNA gene sequence analysis.Drug sensitivity testing showed that the isolate was resistant to doxycycline and florfenicol,but susceptible to enrofloxacin.Artificial experimental infection revealed that the bacteria brought similar symptoms to those healthy fish,and the lethal dosage(LD 50)for P.fulvidraco was 2.51×10^(5) CFU/mL.The HE staining revealed that the bacteria caused considerable histological lesions in the gill,brain,intestine,liver,spleen and kidney of fish,presenting systemic infection.This research confirmed the etiology of“Hole in Head”disease for P.fulvidraco,and preliminarily studied the pathogenicity and drug sensitivity of E.tarda.The results will provide a scientific guidance for the effective treatment of this disease in Pelteobagrus fulvidraco.

关 键 词：黄颡鱼 迟钝爱德华氏菌 裂头病 分离 鉴定 组织病理 

分 类 号：S943[农业科学—水产养殖]