大菱鲆脾肾结节病病原菌的分离和鉴定

Isolation and Identification of Mycobacterium marinum Associated with Splenic and Renal Granuloma Disease of Cultured Turbot (Scophthalmus maximus)

中文关键词: 大菱鲆  海分枝杆菌  分枝杆菌病  结节

英文关键词: Scophthalmus maximus  Mycobacterium marinum  Mycobacteriosis  Granuloma

中文摘要:

      2017年夏季，江苏省连云港市某养殖场大菱鲆出现大规模死亡，发病鱼体表无明显症状，解剖可见脾脏、肾脏出现白色散在结节，从发病鱼的内脏中分离得到1株优势菌SM-Myco001。人工感染实验结果显示，SM-Myco001可以引起大菱鲆内脏结节症状并造成鱼类死亡，且在高养殖水温(22℃)条件下发病更为剧烈。生理生化鉴定和16S rRNA基因分析结果显示，SM-Myco001属于海分枝杆菌(Mycobacterium marinum)。本研究首次报道了我国养殖大菱鲆感染海分枝杆菌的病例，可为大菱鲆养殖过程中的疾病防控提供参考。

英文摘要:

      With the highest annual production among flatfish, turbot (Scophthalmus maximus) is reared as the major industrial aquaculture marine fish species in North China. In the culture process, members of this species are subject to infection with a variety of pathogens. In 2017, massive death of reared turbot occurred in a farm in Lianyungang City, Jiangsu Province. Externally, no clinical signs were observed for most of the diseased fish. However, after dissection, splenic and renal tubercles were found in all the diseased fish. Homogeneous colonies were isolated from diseased or moribund fish and were named as SM-Myco001. Healthy turbot were subjected to challenge tests by intraperitoneal injection using SM-Myco001. SM-Myco001 was found capable of causing death in turbot, especially at a higher water temperature (22℃). The diseased turbot displayed clinical signs, such as splenic and renal tubercles, similar to those observed in naturally infected fish. SM-Myco001 was identified as Mycobacterium marinum based on bacterial morphology, analytical profile index identification, and 16S rRNA gene sequencing. This study suggests that a strain of M. marinum is the causal agent of splenic and renal tubercle disease in turbot. As a first report, to our knowledge, this study provides a new perspective on disease control in the flat fish aquaculture industry in China.