| 莫金凤,周萌,李国章,等.一株鹅-鱼养殖环境下罗非鱼无乳链球菌的分离鉴定及药物敏感性分析[J].广东农业科学,2024,(6-7):- |
|
PDF
HTML
一株鹅-鱼养殖环境下罗非鱼无乳链球菌的分离鉴定及药物敏感性分析 |
| Isolation, identification and drug sensitivity testing of a strain of Streptococcus agalactiae in tilapia (Oreochromis niloticus) from goose-fish polyculture environment |
| 投稿时间：2024-02-22 修订日期：2024-03-07 |
| DOI： |
| 中文关键词: 罗非鱼 无乳链球菌 鹅-鱼立体养殖模式 药物敏感性；生长特性；致病性 |
| 英文关键词: tilapia Streptococcus agalactiae polyculture model of goose-fish drug sensitivity |
| 基金项目: |
|
| 摘要点击次数: 42 |
| 全文下载次数: 0 |
| 中文摘要: |
| 【目的】为确定鹅-鱼立体养殖环境下爆发罗非鱼疾病的病原,通过分析病原菌的生长特性、致病性与药物敏感性,为罗非鱼病的深入研究与精准防控提供科学参考数据。【方法】本文从患病罗非鱼的脏器中分离细菌,采用形态观察、生理生化鉴定、16S rRNA 基因序列分析等方法鉴定菌株；绘制菌株的生长曲线,分析温度、盐度及pH对病原菌生长的影响；通过腹腔注射及拌料口服投喂方式人工感染健康罗非鱼了解菌株的致病性；采用药敏纸片法测定菌株对11类共26种抗菌药物的敏感性。【结果】结果显示,从患病罗非鱼的脑组织中分离纯化得到优势菌株SA20160722YJN,经形态学观察、生理生化鉴定、16S rRNA 基因序列分析及人工回归感染试验,鉴定此菌株为该罗非鱼病的主要病原菌无乳链球菌；SA20160722YJN菌株的生长迟缓期为0~5 h,对数期为5~12 h；最适生长温度为37 ℃,最适pH值为7.0,最适盐度为5‰。SA20160722YJN菌株通过腹腔注射和拌料口服投喂方式均可感染健康罗非鱼；在(29±1) ℃的水温中,腹腔注射方式对罗非鱼有较强的致病性,半数致死浓度为2.4×108 CFU/mL；菌株致病力的强弱与细菌浓度和水温密切相关。SA20160722YJN菌株对甲氧苄啶、庆大霉素、新霉素等6种药物产生耐药性,对恩诺沙星、环丙沙星、阿米卡星等4种药物中度敏感,对多西环素、氟苯尼考、利福平等16种药物敏感。【结论】研究结果表明,无乳链球菌是鹅-鱼立体养殖环境下罗非鱼疾病爆发的主要病原菌,该病原菌的致病力强弱与细菌浓度和水温密切相关。 |
| 英文摘要: |
| 【Objective】In order to investigate the cause of the tilapia disease outbreak in the geese-fish polyculture system, the growth characteristics, pathogenicity and drug sensitivity of the bacteria responsible were analyzed. This study aims to provide valuable scientific data for further research and effective prevention and control measures against tilapia disease. 【Methods】 Bacteria were isolated from the organs of diseased tilapia and identified using vaious methods such as morphological observation, physiological and biochemical identification, and16S rRNA gene sequence analysis. The impact of temperature, salinity and pH on the growth of pathogenic bacteria were analyzed, and a growth curve for the strain was plotted. The pathogenicity of the bacterial strain was assessed by intraperitoneal injection and oral feeding of mixed materials. Additionally, the susceptibility of the strain to 26 different antimicrobial agents belonging to 11 classes was determined using the drug sensitive disk method. 【Results】The dominant strain SA20160722YJN was isolated and purified from the brain tissue of infected tilapia. Through various methods including morphological observation, physiological and biochemical identification, 16S rRNA gene sequence analysis, and artificial regression infection test, the strain was identified as Streptococcus agalactiae (S. agalactiae), the main pathogen causing tilapia disease. The growth retardation stage of SA20160722YJN was 0~5h, and its logarithmic stage was 5~12h. The optimal conditions for growth are found to be a temperature of 37 ℃, pH value of 7.0, and salinity of 5‰. In an artificial infection test by intrabitoneal injection, the strain SA20160722YJN showed high pathogenicity to tilapia at a temperature of (29±1) ℃, with a lethal concentration of 2.4×108 CFU/mL. The pathogenicity of the strain was found to be closely related to bacterial concentration and water temperature. Further, the SA20160722YJN strain displayed resistance to six drugs, including trimethopridine, gentamicin and neomycin. It showed moderate sensitivity to four drugs, including enrofloxacin, ciprofloxacin and amikacin. Additionally, it was found to be sensitive to 16 drugs such as doxycycline, flufenicol, rifampicin. 【Conclusion】 This study concludes that Streptococcus agalactiae is the primary pathogen responsible for the outbreak of tilapia disease in the polyculture environment of goose-fish. Furthermore, it is found and the pathogenicity of this pathogen is strongly influenced by the bacterial concentration and water temperature. |
|
查看/发表评论 下载PDF阅读器 |
|
|
|
