1株猪葡萄球菌强毒株的分离鉴定及致病性试验  

Isolation and identification of a high virulent Staphylococcus hyicus and its pathogenic to piglets

作　　者：李艳[1] 张乐宜[1] 宋长绪[1] 

机构地区：[1]广东省农业科学院动物卫生研究所/广东省兽医公共卫生公共实验室,广东广州510640

出　　处：《中国兽医学报》2015年第9期1456-1462,共7页Chinese Journal of Veterinary Science

基　　金：广东省科技厅资助项目(2012A020200014);广州市科技计划资助项目(2012J4100064);广东省生猪产业体系资助项目(粤农2009-380);广东省农业科学院院长基金资助项目(201313)

摘　　要：为确定广东省增城某猪场产房仔猪暴发渗出性皮炎的致病菌,从病猪心脏、肺脏、病变皮肤分离并纯化细菌,经形态学观察,镜检,生化特性及gap基因的序列分析,确定为猪葡萄球菌,命名为ZC-4株。药敏试验结果显示该菌株对头孢拉定、头孢唑啉、新生霉素高度敏感,对头孢噻肟、万古霉素、庆大霉素中度敏感,对青霉素、阿莫西林、磺胺类药物、链霉素、恩诺沙星等均耐药。对分离株毒素基因进行检测,结果显示,分离株携带ExhA毒素基因,测序结果表明,其编码区全长为822bp,编码274个氨基酸;氨基酸序列与丹麦分离株ExhA基因(AF515453)的同源性最高,为99.6%;遗传进化分析显示,分离株所携带的毒素基因与参考菌株猪葡萄球菌ExhA毒素基因聚类紧密,位于一个小的分支内。分离株致病性试验结果显示,分离株接种25日龄健康断奶仔猪后24h,病猪耳根、四肢内侧、背部、腹部、臀部、尾根等部位出现蜕皮并露出有液体渗出的鲜红创面,继而皮肤形成一层厚厚的结痂,说明该菌株具有较强的致病性。本试验为猪葡萄球菌疫苗的研制及致病机制研究提供了理论依据。In order to determine the etiologic agent leading to exudative epidermitis in delivery room piglets of one pig farm in Zengcheng of Guangdong province, bacteria from sick piglets heart, lung, skin lesions were separatied, purified and identified by the morphological observation, microscopic examination, biochemical properties and gap of the gene sequence analysis. The bacterium was de termined to be a staphylococcus hyicus, named ZC-4 strain. Drug susceptibility test results showed that the strain of cephalosporins was highly sensitive to cefazolin, sensitive to novobiocin and mod- erately sensitive to cefotaxime, vancomycin, gentamicin, However resistant to penicillin, amoxicillin,sulfa drugs,streptomycin. The isolate carried exfoliative toxin ExhA with coding region 822 bp and encoded 274 amino acids. Homological analysis indicated that the deduced amino acid sequence of ET gene of the isolate displayed 99. 6G identity, with the ExhA gene of Danish strain （AF515453）. Phylogenetic analysis showed that the ET gene of the isolate closely clustered with ExhA gene of S. hyicus in a small branch. The pathogenicity test indicated that, after the 25-day old piglets were inoculated with the isolate, moulting or red wounds with diffusate appeared in ears,the inside of the limbs, back, abdomen, hips and the tail, and then a thick layer of skincrusting was formed 24 hours post inoculation,indicating strong pathogenicity of the isolate. This study provided theoretical basis for vaccine development of S. hyicus and prevention of disease caused by S. hyicus.

关 键 词：猪渗出性皮炎 猪葡萄球菌 脱落毒素 致病性 

分 类 号：S852.61[农业科学—基础兽医学]