草鱼致病性类志贺邻单胞菌的分离与鉴定

Isolation and identification of a pathogenic Plesiomonas shigelloides from diseased grass carp

摘要:

摘要:【目的】分离鉴定引起草鱼(Ctenopharyngodon idellus)肌肉糜烂的类志贺邻单胞菌(Plesiomonas shigeloide)菌株JX-09。【方法】从患病草鱼分离致病菌，经形态学观察、人工感染试验、生理生化特性测定和16S rRNA基因序列分析对其进行分类鉴定和致病性检验;同时对分离到的菌株做药物敏感性试验。【结果】从回归感染后的草鱼体内再次分离到菌株JX-09，表明该菌株为致病菌;菌株JX-09对草鱼的半致死量为6.4×104cfu/g。通过生化特征和分子系统学分析，将菌株JX-09鉴定为类志贺邻单胞菌。药敏试验表明该菌株对氨曲南、头孢唑林、头孢噻吩、头孢曲松等头孢类药物敏感，对卡那霉素、麦迪霉素、万古霉素和哌拉西林等耐药。【结论】类志贺邻单胞菌是草鱼肌肉糜烂病的致病菌，这是首次报道了该菌对草鱼有致病性。

Abstract:

Abstract:［Objective］The aim of this study is to identify strain JX-09 and confirmed that the strain is the pathogen of diseased grass carp (Ctenopharyngodon idellus).［Methods］A pathogenic strain JX-09 was isolated from the diseased grass carp. The strain was identified based on physiological and biochemical characteristics，and the sequence analysis of 16S rRNA．Virulence of strain JX-09 to healthy grass carp was also tested．Furthermore，drug sensitivity was detected with Kirby-Bauer’s agar diffusion method．［Results］ Strain JX-09 was identified as Plesiomonas shigelloides by biochemical analysis and molecular biology．The P．shigelloides strain was re-isolated from the artificial infected grass carp，and the LD50 was about 6.4×104 cfu/g．Drug sensitive tests showed that strain JX-09 was susceptible to aztreonam，cefazolin，cephalothin and ceftriaxone，and resistant to kanamycin， medicamycin，vancomycin and piperacillin．［Conclusion］Strain JX-09 was the pathogen of grass carp with muscle erosive disease．To the best of our knowledge，this is the first report that P．shigelloides as the pathogenic strain of grass carp.