猪链球菌7型的分离鉴定及致病性研究  

Isolation,identification and pathogenicity of Streptococcus suis type 7

作　　者：姜志康 韩先杰[1] 郭皖露 陈超[1] 柳宇 刘康 王贤文 郝炬源 刘刚 JIANG Zhikang;HAN Xianjie;GUO Wanlu;CHEN Chao;LIU Yu;LIU Kang;WANG Xianwen;HAO Juyuan;LIU Gang(College of Veterinary Medicine,Qingdao Agricultural University,Qingdao 266109,China)

机构地区：[1]青岛农业大学动物医学院,山东青岛266109

出　　处：《中国兽医科学》2025年第2期182-187,共6页Chinese Veterinary Science

基　　金：国家自然科学基金青年基金项目(32200151);山东省自然科学基金青年基金项目(ZR2022QC043);山东省重大科技创新工程项目(2019JZZY010720);山东省现代农业产业技术体系生猪创新团队资助项目(SDAIT-08-10)。

摘　　要：为探究猪链球菌7型的致病性,笔者从山东半岛地区病死猪体内分离纯化病原菌,经革兰染色、生化鉴定、PCR鉴定,共分离出4株猪链球菌7型,通过小鼠感染试验测定半数致死量,临床症状观察及组织病理切片分析猪链球菌7型的致病性。结果显示,细菌于血平板上呈现圆形或椭圆形的灰白色半透明菌落,菌落周围呈现β溶血环;革兰染色为阳性,菌落呈单个、多个或链条形排列;API 20 Strep生化鉴定结果为链球菌属,PCR扩增cps7结果为阳性。动物试验确定SS7-4菌株对BALB/c小鼠致病力最强,LD_(50)为2.35×10^(4) CFU/mL,攻毒组小鼠各组织肿胀出血严重,器官边缘钝圆,颜色变深,呈暗红色或黑红色。组织病理学观察为心肌纤维断裂,脾小梁异常增多,肾小管肿胀明显,肺充血严重。本试验结果为深入研究猪链球菌7型的致病机理奠定了基础。In order to investigate the pathogenicity of Streptococcus suis type 7,the bacteria were isolated and purified from diseased pigs in the Shandong peninsula.Four strains of type 7 were identified by Gram staining,biochemical identification and PCR.The pathogenicity of S.suis type 7 was verified by mouse infection test,the median lethal dose was determined,and clinical symptoms and histopathological sections were observed.The results showed that the bacteria appeared as round or oval pale translucent colonies on the blood plate,withβ-hemolytic rings around the colonies.Gram staining was positive,and the colonies were arranged in single,multiple,or chain patterns.API20 strep biochemical identification results were Streptococcus genus,and PCR amplification of cps7 results were positive.Animal experiments showed the SS7-4 strain had the strongest pathogenicity to BALB/c mice,with a LD_(50) of 2.35×10^(4) CFU/mL.The tissues of mice in the challenge group were severely swollen and bleeding,the edges of the organs were blunt and the color became dark red or black red.Histological observations showed myocardial fiber rupture,abnormal increase in spleen trabeculae,obvious swelling of renal tubules,and severe congestion of lungs.The results of this experiment lay the foundation for further study of the pathogenic mechanism of S.suis type 7.

关 键 词：猪链球菌7型 分离鉴定 动物试验 BALB/C小鼠 致病性 

分 类 号：S852.612[农业科学—基础兽医学]