异育银鲫源杀鲑气单胞菌杀鲑亚种的分离鉴定

Identification of Aeromonas salmonicida subsp. salmonicida isolated from Carassius auratus gibelio

摘要:

【目的】分离鉴定江苏省扬州市养殖场异育银鲫患病病原。【方法】采用常规的理化特性和分子生物学的方法，对从濒死异育银鲫肝脏处分离到的菌株 YZ-1进行表型生物学、分子生物学及药敏试验的系统研究。【结果】该菌株 16S rRNA基因(序列长度 1 446 bp，GenBank登录号为 JX164202)与其它杀鲑气单胞菌 16S rRNA基因一致性在 99%?100%之间，构建发育树确定该菌株为杀鲑气单胞菌杀鲑亚种(Aeromonas salmonicida subsp. salmonicida)。人工回感可导致异育银鲫死亡。药敏试验结果显示：对头孢呋辛、复方新诺明、恩诺沙星等23种抗生素敏感；对阿米卡星、四环素、大观霉素、头孢拉定等 11种抗生素中度敏感；对青霉素 G、链霉素、庆大霉素、氟苯尼考、万古霉素等10种抗生素耐药。【结论】研究结果证实引起异育银鲫死亡的病原为杀鲑气单胞菌杀鲑亚种。

关键词:异育银鲫(Carassius auratus gibelio)，杀鲑气单胞菌杀鲑亚种(Aeromonas salmonicida subsp. salmonicida)，16S rRNA基因，药敏试验

Abstract:

[Objective] A continuous high mortality of Carassius auratus gibelio occurred in a farm of Yangzhou area in Jiangsu Province. [Methods] A purely cultured strain (YZ-1) isolated from liver of sick Carassius auratus gibelio, and its main morphological physiological and biochemical characteristics were examined. [Results] For further confirmation on molecular level, 16S rRNA gene was sequenced; and the accession number in GenBank is JX164202 in length of 1 446 bp. Sequences analysis on the 16S rRNA gene shows that it is very similar to other Aeromonas salmonicida, and their nucleotide homology was between 99% to 100%. Its phylogenetic tree showed that the pathogen isolated from the diseased C. auratus gibelio was identified as Aeromonas salmonicida subup. salmonicida isolate. The challenge test using YZ-1 displayed that the prevalence of symptoms and spontaneous onset symptoms were the same. The antibiotic sensitivity using 44 antimicrobial agents showed that the isolate was sensitive to 23 agents, including cefuroxime, cotrimoxazole, enrofloxacin, and cephradine; sensitive slightly to 11 agents, including amikacin, tetracycline, norfloxacin, spectinomycin, and cefradine; and resistant to 10 agents, including peillin G, streptomycin, gentamicin, florfenicol, and vancomycin. [Conclusion] The death of Carassius auratus gibelio is caused by Aeromonas salmonicida subup. salmonicida.

Key words:Carassius auratus gibelio, Aeromonas salmonicida subsp. salmonicida, 16S rRNA gene, Drug sensitivity test