贵州省水产动物源嗜水气单胞菌耐药质粒的中草药消除作用研究

Aeromonas hydrophila is a typical pathogen of people-beast-fish zoonotic disease. The bacterial septicemia of freshwater fish caused by Aeromonas hydrophila is classified as second kind of loemia in China, which gave rise to huge economic losses in aquaculture. Abuse of antibiotics led to the occurence of multiple drug-resistant strains, and plasmid with resistant genes transfers between strains rapidly, causing a direct threat to human life and health. Chinese herbal medicine has advantages of natural, little side effects and safety in body, and its curing effect of resistance plasmid has become a domestic research hot spot. This study investigates the antibiotic resistance of Aeromonas hydrophila of various aquatic animals from multiple aquiculture zones through antimicrobial susceptibility test and formulates the resistance spectrum. Then we detect the resistance plasmid through DNA fingerprinting, conjugation study and plasmid curing test by physicochemical factors. Moreover, plasmid curing tests in vitro and vivo are conducted to screen out effective components and compounds of Chinese herbal medicine, and explore the resistance plasmid curing effect of Chinese herbal medicine in practical application. These results provide theoretical basis for explaining the mechanism of the curing resistance plasmid by Chinese herbal medicine, and establishing a foundation for suppressing the shift and spread of drug resistance gene. As the same time, these results have constructive significants in standardizing drug use in aquaculture, reducing environmental pollution and improving the safety of aquatic products.

嗜水气单胞菌是典型的人-兽-鱼共患病病原菌，其引起的淡水鱼细菌性败血症为我国二类疫病，给水产养殖业造成巨大的经济损失。抗生素的滥用导致了嗜水气单胞菌多重耐药株的出现，并且带有耐药基因的耐药质粒可以在菌株间高频率转移，给人类的生命健康构成直接威胁。中草药具有天然、毒副作用小、体内使用安全等优点，其耐药质粒消除作用已成为国内研究热点。本项目通过药敏实验检测来源于贵州省多个养殖区、多种水产养殖动物的嗜水气单胞菌的耐药性并绘制耐药谱；通过DNA指纹图谱、接合传递试验、理化因子质粒消除试验等鉴定耐药质粒；通过体外和体内质粒消除试验筛选出具有广谱质粒消除作用的中草药有效成分及复方中草药，探讨中草药在实际应用中对嗜水气单胞菌耐药质粒的消除作用。本项目为阐明中草药消除耐药质粒的机理提供理论依据，也为遏制耐药基因的转移和扩散奠定基础，更对规范水产用药、减少环境污染、提高水产品安全具有建设性的意义。

嗜水气单胞菌是典型的人-兽-鱼共患病病原菌，其引起的淡水鱼细菌性败血症为我国二类疫病，给水产养殖业造成巨大的经济损失。抗生素的滥用导致了嗜水气单胞菌多重耐药株的出现，并且带有耐药基因的耐药质粒可以在菌株间高频率转移，给人类的生命健康构成直接威胁。中草药具有天然、毒副作用小、体内使用安全等优点，其耐药质粒消除作用已成为国内研究热点。本项目从不同水生环境、水生动物体内中分离得到嗜水气单胞菌26株，药敏试验结果显示这些分离株对恩诺沙星和氟苯尼考的敏感性相对较高，对其他常用的抗生素均有较强的抗性，实际生产过程中可选择这两种药物对嗜水气单胞菌性疾病进行治疗。耐药基因PCR鉴定和接合传递试验结果表明菌株27S5X1携带可在菌株间转移的耐药质粒，该质粒存在aac(6’)，tetB，tetC，cmlE，catB1，catB2，catB3，blaOXA-9和sul 2等7个耐药基因。通过对29种中药有效成分、41种中草药水煎液及62组不同配伍复方中草药进行体外消除菌株27S5X1的耐药质粒试验，试验结果表明有7组复方中草药有效成分和5组复方中草药水煎液消除效果较高。体外消除效果最好的复方中药水煎液（紫花地丁：大青叶：厚朴：高良姜=1:1:1:1）其斑点叉尾鮰体内消除率可达28.6%。本项目为阐明中草药消除耐药质粒的机理提供理论依据，也为遏制耐药基因的转移和扩散奠定基础，更对规范水产用药、减少环境污染、提高水产品安全具有建设性的意义。