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广东省某养殖场南美白对虾于2012年突发传染病,为确定该病病原并对其进行有效防制,特利用分子生物学技术对病原进行了分离鉴定。结果从发病南美白对虾分离纯化到1株优势菌ZHBX12016,将该菌人工浸浴感染南美白对虾,5 d后南美白对虾死亡率达95%,且发病对虾临床症状与自然病例相似,人工注射感染测得其半数致死量LD50为6.43×103cfu/mL。该菌革兰氏染色阴性,短杆状;对半乳糖、蔗糖、甘露醇、葡萄糖产气、精氨酸双水解酶,赖氨酸脱酸酶,葡萄糖酸盐的生化反应性与豚鼠气单胞菌(Aeromonas caviae)(synonym Aeromonas punctata)生化反应结果相同。用聚合酶链式反应(PCR)技术扩增该菌16S rD NA序列进行测序和生物信息学分析,结果显示:分离菌株与豚鼠气单胞菌(Aeromonas caviae)相似性达97.7%~100%之间,在系统发育树上聚为同一分支。综合该菌形态学、致病性、生理生化和16S rRNA基因分析结果,将其鉴定为豚鼠气单胞菌(Aeromonas caviae)。药敏试验结果表明分离菌株对氯霉素、土霉素、丁胺卡那、呋喃唑酮等高度敏感。
In a farm in Guangdong Province, P. vannamei was a pandemic infectious disease in 2012. To identify the pathogen of the disease and to effectively control it, we used molecular biology techniques to isolate and identify the pathogen. Results A dominant strain, ZHBX12016, was isolated and purified from the infected P. vannamei. The bacteria were immersed in P. vannamei for 5 d. The mortality of S. prawn was 95% after 5 days. The clinical symptoms of P. shrimp were similar to those of natural cases. The median lethal LD50 of infection was 6.43 × 103 cfu / mL. The bacteria Gram-negative, short rod-shaped; on galactose, sucrose, mannitol, glucose gas production, arginine dihydrolase, lysine deacidification enzyme, gluconic acid biochemical reactivity with guinea pig gas single Aeromonas caviae (synonym Aeromonas punctata) The same biochemical reaction results. The 16S rDNA sequence of this strain was amplified by polymerase chain reaction (PCR) and sequenced and analyzed by bioinformatics. The results showed that the isolates were 97.7% ~ 100% similar to Aeromonas caviae Between the same branch in phylogenetic tree. Based on the morphological, pathogenicity, physiological and biochemical characteristics and 16S rRNA gene analysis, the strain was identified as Aeromonas caviae. Susceptibility test results showed that isolates were highly sensitive to chloramphenicol, oxytetracycline, amikacin and furazolidone.