蛙类歪头、破头与白眼综合征病原分析

Analysis on pathogens of frogs with crooked head,broken head or white eye

为探明湖北、福建等主养区一系列蛙疾病的发病原因,从具有典型歪头、破头与白眼等症状的蛙脑部和内脏器官分离到40株优势菌。经16S rRNA基因序列比对,发现40株优势菌均与米尔伊丽莎白菌(Elizabethkingia miricola)同源。经生理生化鉴定、系统发育分析发现,这40株优势菌存在遗传差异,宿主和区域是影响亲缘关系的重要因素,并判定菌株典型株QW08为米尔伊丽莎白菌。回归感染实验证实QW08为蛙类歪头、破头与白眼病的病原菌。组织病理学观察显示,米尔伊丽莎白菌感染黑斑蛙可引起其全身多脏器与组织损伤,脑、肠道、肝、脾与肾等组织器官损伤极其严重,主要病理变化表现为变性、坏死和炎症反应,致多组织器官功能障碍而引起感染蛙死亡。药敏特性分析显示,分离株QW08仅对氟苯尼考高度敏感,对其余19种抗生素表现出不同程度的耐药。研究结果为蛙类该病防控提供了理论依据。

In order to investigate the causes of a series of frog diseases in the main breeding areas of Hubei and Fujian, more than 40 strains of dominant bacteria were isolated from the brain and internal organs of frogs with typical symptoms of crooked head, broken head or white eyes. Through 16 S rRNA gene sequence alignment, it was found that 40 dominant strains were homologous with Elizabethkingia miricola. After physiological and biochemical identification and phylogenetic analysis, the genetic differences were found in 40 dominant strains, the cluster analysis of 40 strains showed that host and region were important factors affecting genetic relationship, and the typical strain QW08 was identified as E. miricola. By regression infection experiment, strain QW08 was confirmed to be the pathogen of crooked head, broken head and white eye disease in frogs. Histopathological observations showed that E. miricola infection could cause damage to multiple organs and tissues in the whole body, including brain, intestinal tract, liver, spleen and kidney. The main pathological manifestations were degeneration, necrosis and inflammation, leading to dysfunction of multiple organs and tissues and death of infected frogs. Drug sensitivity analysis showed that QW08 was only highly sensitive to florfenicol, and showed different degrees of resistance to the other 19 antibiotics. The results provided a theoretical basis for the prevention and control of the disease in frogs.