摘要
为查明天津武清区某养殖场拉氏鱥(Rhynchocypris lagowskii)发病原因,从患病拉氏鱥腹水中分离纯化菌株,通过形态学观察、16S rDNA基因序列及其系统发育分析,确定其分类地位,利用药敏纸品扩散法检测其耐药特性。结果表明,分离到1株优势菌(LSH202101),在LB平板上形成淡黄色、不透明,菌落边缘整齐、中间微微隆起、表面光滑,直径约2 mm的圆形菌落;16SrDNA序列比对结果显示,该序列与温和气单胞菌(登录号:KC951914)的相似程度最高,达到99%,与温和气单胞菌聚为一支该菌株,结合生理生化试验结果,认为LSH202101为温和气单胞菌。人工回归感染试验结果显示,人工感染LSH202101菌株的拉氏鱥死亡率为93.3%,且其腹水中分离出的细菌与菌株LSH202101生理生化特性相同。因此认为温和气单胞菌为拉氏鱥腹水症的病原。该菌株对庆大霉素、硫酸新霉素、氟苯尼考、恩诺沙星等4种抗菌药物敏感,对复方新诺明、卡那霉素、四环素、多西环素耐药。
To identify the cause of disease in Rhynchocypris lagowskii at a farm in Wuqing District,Tianjin,bacterial strains were isolated and purified from the ascitic fluid of diseased R.lagowskii.Their taxonomic status was determined through morphological observation,16S rDNA gene sequence analysis,and phylogenetic analysis,while their drug resistance characteristics were detected using the disk diffusion method.The results showed that one dominant bacterial strain(designated as LSH202101)was isolated.On the LB agar plate,this strain formed circular colonies with the following characteristics:pale yellow color,opaque appearance,neat colony edges,slightly raised center,smooth surface,and a diameter of approximately 2 mm.16S rDNA sequence alignment results revealed that this sequence had the highest similarity(up to 99%)with that of Aeromonas sobria(accession number:KC951914)and clustered together with A.sobria in the phylogenetic tree.Combined with the results of physiological and biochemical tests,the strain LSH202101 was identified as A.sobria.The results of the artificial regression infection test indicated that the mortality rate of R.lagowskii artificially infected with the LSH202101 strain was 93.3%,and the bacteria isolated from the ascitic fluid of the infected fish had the same physiological and biochemical characteristics as the LSH202101 strain.Therefore,it was concluded that A.sobria is the pathogen causing ascites disease in R.lagowskii.In terms of drug sensitivity,this strain was sensitive to 4 antimicrobial agents,including gentamicin,neomycin sulfate,florfenicol,and enrofloxacin,while it was resistant to sulfamethoxazole-trimethoprim,kanamycin,tetracycline,and doxycycline.
作者
于建胜
黄俊佳
罗璋
姬炳林
白晓慧
YU Jiansheng;HUANG Junjia;LUO Zhang;JI Binglin;BAI Xiaohui(Agricultural Development Service Center of Wuqing district,Tianjin 300061,China;Rural Development Service Center of Wuqing district,Tianjin 300061,China;Tianjin Fisheries Research Institute,Tianjin 300221,China;Tianjin Agricultural University,Tianjin 300384,China)
出处
《水产养殖》
2025年第10期17-20,38,共5页
Journal of Aquaculture
基金
天津市科技计划项目(22ZYCGSN00820,24ZYCGSN01270)
天津市淡水产业技术体系创新团队项目(ITTFRS-2021000,ITTFRS2021000-008)。
关键词
拉氏鱥
温和气单胞菌
鉴定
药物敏感性
Rhynchocypris lagowskii
Aeromonas sobria
Isolate
Drug sensitivity
