| 摘要: |
| 从患"摇头病"清溪乌鳖（Pelodiscus sinensis nigrum）的肝脏、脾脏、肾脏、肺组织中分离得到1株细菌。菌落为圆形乳白色凸起，融蜡状，表面光滑，边缘清晰整齐；对该菌进行染色镜检可见其为革兰氏阳性杆菌，呈单个或链状排列。结合生理生化检测结果、16S rDNA基因和gyrB基因和rpoB基因序列分析以及系统进化树结果，该菌株为蜡样芽孢杆菌群（Bacillus cereus group）内新种。用不同浓度的分离菌腹腔注射感染健康的清溪乌鳖，观察发现死亡的清溪乌鳖出现与自然发病鳖相似的症状且从病鳖内脏中可分离得到同样的菌；经统计和计算，其LD50为2.42×105 CFU/kg体重。应用纸片扩散法对14种常用抗菌药物进行药敏试验，结果显示，分离菌对头孢氨苄、氟苯尼考、强力霉素、恩诺沙星、氧氟沙星五种药物敏感；对利福平、头孢他啶则耐药。本研究为清溪乌鳖细菌性病原的报道，旨在为该病的确诊与防治提供科学依据和参考。 |
| 关键词: 清溪乌鳖(Pelodiscus sinensis nigrum) 蜡样芽孢杆菌(Bacillus cereus) 分离鉴定 药敏分析 |
| DOI：10.11693/hyhz20191200281 |
| 分类号:S974.1 |
| 基金项目:浙江省水产新品种选育重大专项项目，2016C02055-4号；浙江省公益类科研院所扶持专项，2019YSZX004号。 |
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| ISOLATION AND IDENTIFICATION OF PATHOGEN CAUSING “HEAD-SHAKING SYNDROME” OF PELODISCUS SINENSIS NIGRUM AND DRUG SUSCEPTIBILITY ANALYSIS |
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LI Yan-Li1,2, ZHANG Hai-Qi1, Lü Sun-Jian1, LIN Feng1, LIU Li1, YUAN Xue-Mei1, SU Sheng-Qi2
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1.Zhejiang Institute of Freshwater Fisheries, Huzhou 313001, China;2.College of Animal Science and Technology, Southwest University, Chongqing 400715, China
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| Abstract: |
| A strain of bacteria was isolated from the liver, spleen, kidney, lung of diseased Pelodiscus sinensis nigrum with "head-shaking syndrome". The bacterial colonies were round milky white bulge, waxy, smooth, and the edge was clear and neat. The bacteria was Gram-positive in single or chain arrangement in staining microscopy. Combined with the results of physiological and biochemical test, sequence analysis of the 16S rDNA gene, gyrB gene and rpoB gene, and phylogenetic grouping, the strain was confirmed as a new species of Bacillus cereus group. Different concentrations of isolated bacteria were used to intraperitoneally inject into healthy Pelodiscus sinensis nigrum, and it was observed that the dead Pelodiscus sinensis nigrum showed symptoms similar to those naturally diseased ones in the farming, and the same bacteria were isolated from the viscera of the diseased. According to statistics and calculation, the LD50 was 2.42×105 CFU/kg. Results show that the isolates were sensitive to cefalexin, florfenicol, doxycycline, enrofloxacin, and ofloxacin, and resistant to rifampicin and ceftazidime. This study is a report on the bacterial pathogen of Pelodiscus sinensis nigrum, and may provide a scientific basis and reference for the diagnosis and treatment of the disease. |
| Key words: Pelodiscus sinensis nigrum Bacillus cereus separation and identification antimicrobial susceptibility test |
