杂交鲟鲁氏耶尔森氏菌的分离鉴定及感染的病理损伤

摘要

[Objective]To explore the etiology of a serious infectious disease occured in hybrid sturgeon(Acipenser schrencki♀×A.baeri♂)from a farm of Qionglai,Sichuan Province.[Method]The pathogens were isolated from the liver,spleen and kidney tissues of diseased fish,and identified by physicochemical characteristics,16S rRNA and gyrB gene sequences analyses,meanwhile the susceptibility test and histopathological observation were performed.[Result]One gram-negative predominant bacteria strain(YC160412)was isolated and identified as Yersinia ruckeri by physicochemical characteristics,16S rRNA and gyrB gene sequences analyses.The antibiotic susceptibility test showed that the pathogen was sensitive to cefazolin,ampicillin,florfenicol,and resistant to amoxicillin and erythromycin.Histopathological observation found that Y.ruckeri infection caused significant damages to hybrid sturgeon multiple organs,especially in liver,spleen,kidney,intestine and gill.The main pathologic lesions were obvious degeneration,necrosis,hemorrhage and infiltration of the inflammation cells.The pathogen was largely found in liver,spleen and kidney tissues.[Conclusion]This study confirms Y.ruckeri is the pathogen of the epidemic.Its infection can cause multiple organ dysfunctions and even death of hybrid sturgeon.%[目的]探究四川省邛崃市某养殖场的杂交鲟Acipenser schrencki ♀×A.baeri ♂暴发的传染病病因.[方法]从病鱼的肝、脾和肾组织中进行病原菌的分离,结合理化特征和16S rRNA及gyrB基因序列分析对其进行鉴定,同时进行药敏试验及病理损伤观察.[结果]分离到1株G–优势菌(YC160412),通过理化特征分析,16S rRNA及gyrB基因序列分析鉴定分离菌为鲁氏耶尔森氏菌Yersinia ruckeri;药敏试验表明,该病原菌对头孢唑啉、氨苄西林、氟苯尼考等抗生素敏感,对阿莫西林、红霉素等耐药;病理组织学观察发现,鲁氏耶尔森氏菌感染杂交鲟对多组织器官都造成明显的损伤,尤其是肝、脾、肾、肠和鳃,表现为明显的变性、坏死、出血及炎症细胞的浸润,同时在肝、脾和肾组织内有大量病菌分布.[结论]证实了鲁氏耶尔森氏菌是本次疫情的病因,其感染引起杂交鲟多组织器官功能障碍而死亡.