摘要：【目的】查明引起达氏鲟（Acipenser dabryanus）发病死亡的病原菌及其耐药性，为该病的临床诊断和科学防治提供参考依据。【方法】以常规方法对患病达氏鲟的鳃、心脏、肝脏和肠道等组织进行病原菌分离纯化，采用形态学观察、生理生化特性鉴定与16S rRNA序列分析相结合的方法进行鉴定，通过人工感染试验明确病原菌的致病性及其病理组织学特征，并以K-B纸片扩散法进行药敏试验。【结果】从患病达氏鲟的肝脏组织中分离获得一株优势菌株（AD-AV201606），经形态学观察、生理生化特性鉴定及16S rRNA序列分析，最终鉴定为维氏气单胞菌（Aeromonas veronii）。以维氏气单胞菌人工感染达氏鲟，可复制出与自然发病相同的临床症状，感染引起的死亡率为50%～80%，且病鱼集中在感染后1～3 d死亡。药敏试验结果表明，达氏鲟维氏气单胞菌对庆大霉素、链霉素、左氧氟沙星、四环素、环丙沙星、阿奇霉素和头孢呋辛等7种抗生素敏感，对青霉素和利福平已产生耐药性。维氏气单胞菌感染对达氏鲟造成的组织病理变化主要集中在肝脏、肠道及鳃组织。【结论】维氏气单胞菌对达氏鲟有较强的致病性，通过引起肝脏、肠道及鳃等器官组织的病理变化而造成机体损伤甚至死亡，生产上可选用庆大霉素、链霉素和四环素进行防治。

关键词： 达氏鲟；维氏气单胞菌；分离鉴定；药敏试验；病理组织学

中图分类号： S941.42 文献標志码：A 文章编号：2095-1191（2018）06-1235-07

Abstract：【Objective】The present experiment was conducted to investigate pathogenic bacteria that caused death of Acipenser dabryanus and its susceptibility in order to provide references for the clinical diagnosis and scientific prevention of the disease. 【Method】Bacterial isolates were collected from gill， heart， liver and intestines of diseased A. dabryanus by conventional methods. After being purified， the pathogen was identified based on morphological observation， biochemical characteristics together with 16S rRNA sequence analysis. The pathogenicity and histological characteristics of pathogenic bacteria were determined by artificial infection. Drug susceptibility was detected by Kirby-Bauer disk diffusion method. 【Result】A dominant strain（AD-AV201606） was isolated from the liver tissue of the diseased A. dabryanus. The pathogenic bacteria was finally identified as Aeromonas veronii after morphological observation. Biochemical characteristics test together with 16S rRNA sequence analysis. The infection symptoms of the fishes by artificial infection germs appeared the same as the natural infection， with mortality rate of 50%-80%. The infected A. dabryanus died 1-3 d after infection. Drug sensitivity test showed that the isolated bacterium was highly sensitive to seven kinds of antibiotics including gentamicin， streptomycin， levofloxacin， tetracycline， ciprofloxacin， azithromycin and cefuroxime. The bacterium had resistance to penicillin and rifampicin. The histological changes of sturgeon caused by A. veronii infection were mainly concentrated in the liver， intestinal tract and gill tissues. 【Conclusion】A. veronii had strong pathogenicity on A. dabryanus. It leads to body damage and even death of A. dabryanus by causing pathological changes in liver， intestine and gill. Gentamicin， streptomycin and tetracycline can be selected for prevention and treatment of the disease in production.