Isolation and identification of fish pathogen Edwardsiella tarda from mariculture in China
Isolation and identification of fish pathogen Edwardsiella tarda from mariculture in China
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DOI：
10.1111/j.1365-2109.2008.02101.x
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发表时间：
2008-12-22
影响因子：
2
通讯作者：
Zhang, Yuanxing
中科院分区：
文献类型：
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作者：
Xiao, Jingfan;Wang, Qiyao;Zhang, Yuanxing
从中国北方沿海城市烟台某养殖场发生的一次高死亡率的大菱鲆细菌性败血症中分离到病原体。其中7个纯菌株为迟缓爱德华氏菌（Edwardsiella tarda），分别为EH-15、EH-103、EH-107、EH-202、EH-203、EH-305和EH-306。对培养物的表型特征进行了广泛分析。其中3个菌株16 SrDNA序列与E. tarda序列（GenBank登录号EF 467289）。然而，与E. tarda ATCC 15947中，除EH-15外，所有菌株均含有一个大小约为23.7kb的新型大质粒。此外，致病性的菌株进行了实验挑战鱼模型。这些菌株对剑尾鱼表现出较强的毒力，LD 50范围为3.8 x 10（3）至3.8 x 10（5）CFU g（-1），其中EH-202的LD 50值最低。E.测定迟发型病毒分离株。与E. tarda ATCC 15947菌株对氯霉素表现出较强的抗性，其主要的氯霉素抗性决定簇可能是cat III。描述了涡传大肠杆菌的主要生物学特性。本研究为进一步揭示其致病机理提供了有用的信息。
The causative agent was isolated from diseased turbots (Scophthalmus maximus) stricken by a high-mortality outbreak of bacterial septicaemia occurring in a mariculture farm in Yantai, a northern coastal city of China. Seven pure isolates, namely EH-15, EH-103, EH-107, EH-202, EH-203, EH-305 and EH-306, belonged to Edwardsiella tarda. The phenotypic features of the cultures were analysed extensively. Three of the isolates showed high 16S rDNA sequence similarities with E. tarda sequence (GenBank accession no. EF467289). However, unlike the E. tarda ATCC 15947, all the isolates, except EH-15, contained a novel large plasmid sized about 23.7 kb. Furthermore, pathogenicity of the isolates was addressed by experimental challenges with fish models. The isolates exhibited strong virulence to swordtail fish with LD50 ranging between 3.8 x 10(3) and 3.8 x 10(5) CFU g(-1), and EH-202 displaying the lowest LD50 value among them. Antibiotic susceptibilities of E. tarda isolates were assayed. Compared with E. tarda ATCC 15947, the isolates displayed strong resistance to chloramphenicol, and the probable dominant chloramphenicol resistance determinant was cat III. Depicting the main biological properties of turbot-borne E. tarda strains in China, the study provided useful information for further unveiling their pathogenic mechanisms.