中文摘要：

从秦皇岛和胶南患出血病的大菱鲆（Scophthalmus maximus）肾脏中分别分离得到优势菌株MHK。和JN，人工感染实验证实这两株菌对大菱鲆有较强的致病性，半数致死量（LD50）分别为6．30×10^3cfu／尾和2．51×10^4cfu／尾。对病原菌16SrDNA序列对比分析及进化树分析表明，MHK2和JN与迟缓爱德华氏菌（Edwardsiella tarda）高度一致。API ID32E快速鉴定结果表明，MHK2和JN生理生化特征与非致病性迟缓爱德华氏菌标准菌株LSE6一致，属于迟缓爱德华氏菌。经APIZYM酶活检测，MHK2和JN的碱性磷酸盐酶和酸性磷酸酶活性明显高于LSE6这两项酶活特征有望作为区别致病性和非致病性迟缓爱德华氏菌的一个标准。

英文摘要：

Two dominated strains MHK2 and JN were isolated from cultured turbot （Scophthalmus maxirnus） with hamorrhage disease in Qinhuangdao and Jiaonan respectively. Infection experiments showed that two strains were highly pathogenic to turbot. The LD50 of MHK2 is 6.30）〈10^3 cfu/fish, and JN is 2.51× 10^4 cfu/fish. The sequences of 16S rDNA of MHK2 and JN were compared to those in Genbank Datebase. They shared high similarity to Edwardsiella tarda. By API ID32E systematic identification, MHK2 and JN were similar in characteristics to E. tarda standard strain LSE6, and were indentified as E. tarda. By API ZYM enzymatic activity detection, MHK2 and JN were significantly higher in alkaline phosphatase and acid phosphatase activity than those of LSE6. These two charcteristics may be a way to distinguish the pathoge- nicity from the non-pathogenic E. tarda.