棘胸蛙出血性败血症的病原菌分离鉴定与病理学研究  

Isolation and Identification of Pathogenic Bacterium and Pathology of Haemorrhagic Septicaemia of Domestic Frog Quasipaa spinosa

作　　者：任思宇[1,2] 吴春艳 汪开毓[3] 王雯慧[2] 刘震坤[1] 杨延辉[1] REN Siyu;WU Chunyan;WANG Kaiyu;WANG Wenhui;LIU Zhenkun;YANG Yanhui(Chongqing Three Gorges Vocational College,Chongqing 404155,China;College of Veterinary Medicine,Gansu Agricultural University,Lanzhou 730070,China;College of Veterinary Medicine,Sichuan Agricultural University,Chengdu 611130,China)

机构地区：[1]重庆三峡职业学院,重庆404155 [2]甘肃农业大学动物医学院,甘肃兰州730070 [3]四川农业大学动物医学院,四川成都611130

出　　处：《水产科学》2023年第1期102-112,共11页Fisheries Science

基　　金：重庆市教委科学技术研究项目(KJQN202003505,KJQN201803501)。

摘　　要：自患出血性败血症的棘胸蛙肝脏与腹水中分离出1株革兰氏阴性短杆菌,回归感染证实为此次导致棘胸蛙发病的病原菌,该菌对棘胸蛙的半数致死剂量为1.59×10^(6)cfu/g。表型特征鉴定、16S rDNA与gyrB基因测序显示,该分离菌株为嗜水气单胞菌。该菌株对恩诺沙星、四环素、氟苯尼考等药物敏感,对头孢氨苄、青霉素及磺胺异噁唑等药物耐药。组织病理学观察显示,病蛙脾肿大,白髓坏死、面积显著缩小,红髓纤维架构断裂,脾索消失,大量红细胞瘀滞;心外膜极度肿胀,心包内有大量炎性渗出物;肾小管透明变性,肾间质结缔组织松散;肝细胞肿胀,局灶性坏死;脑组织内神经细胞变性坏死。电镜下可见脾内细胞坏死、纤维断裂,巨噬细胞内吞噬有侵染的菌体,网状细胞逐渐转变为黑色素巨噬细胞。试验结果可为川渝地区棘胸蛙的健康养殖与疾病防治提供科学依据。The haemorrhagic septicaemia of domestic frog Quasipaa spinosa was rarely reported.We used conventional bacteriological methods and pathological observations to identify the pathogen and reveal the pathological damage after infection.A gram negative pathogenic bacterium was isolated from liver and ascitic fluid of the diseased frog.Regression infection proved this strain,which had LD50of 1.59×10^(6) cfu/g,was the pathogenic bacterium.According to result of biochemical characteristics test,phylogenetic analysis of 16S rDNA and gyrB gene sequences,this strain was identified as a species of Aeromonas hydrophila.Drug susceptibility showed that the strain was sensitive to enrofloxacin,tetracycline,and florfenicol,and resistance to cefalexin,penicillin and sulfasomizole.The histopathological observation showed obvious damage in spleen with white pulp district decreased and congestion,bleeding and broken fiber in red pulp.The epicardium showed extremely swollen with numerous neutrophils,plasma cells,and monocytes in pericardial cavity.The renal tubular epithelial cell showed hyaline degeneration with monocytes and neutrophilic granulocytes infiltration in the renal interstitial district.The hepatic cells were swollen with focal necrosis,while the neurocytes were degeneration obviously in brain tissue.Transmission electron microscope observation of spleen showed the transformation process for reticular cells to melano-macrophages and necrosis of cells and fiber,while the bacterium was digested in lysosome of macrophages.It was concluded that A.hydrophila was identified as the pathogen causing the symptoms of septicemia.The finding provided theoretical basis for the prevention and treatment of the disease.

关 键 词：棘胸蛙 嗜水气单胞菌 出血性败血症 病理损伤 

分 类 号：S948[农业科学—水产养殖]