一株鸭源粪肠球菌的分离鉴定和致病性检测  

Isolation,identification and pathogenicity test of a strain of Enterococcus faecalis from ducks

作　　者：王海龙 鞠诗婷 马佰贺 王紫苇 路振香[1,2] 李文超 郭伟娜[1,2] WANG Hailong;JU Shiting;MA Baihe;WANG Ziwei;LU Zhenxiang;LI Wenchao;GUO Weina(College of Animal Sciences,Anhui Science and Technology University,Fengyang Anhui 233100,China;Anhui Province Key Laboratory of Animal Nutritional Regulation and Health,Fengyang Anhui 233100,China)

机构地区：[1]安徽科技学院动物科学学院,安徽凤阳233100 [2]动物营养调控与健康安徽省重点实验室,安徽凤阳233100

出　　处：《北京农学院学报》2025年第1期54-61,共8页Journal of Beijing University of Agriculture

基　　金：安徽省教育厅自然科学研究重点项目(KJ2020A0087);安徽科技学院稳定人才项目(DKWD201801);安徽科技学院省级大学生创新课题项目(S202310879062)。

摘　　要：【目的】对送检的病死麻鸭进行粪肠球菌的分离鉴定,并对分离菌的毒力基因、耐药基因和致病性进行检测,为了解该菌的致病机理及防治措施提供参考。【方法】无菌条件下从病死鸭肝脏组织中分离细菌,进行纯化培养、染色镜检、16S rRNA基因序列分析,并对20种抗菌药物的敏感性检测。使用PCR方法扩增其6个毒力基因和11个耐药基因,昆明小鼠攻毒试验检测菌株的致病性。【结果】分离菌为1株革兰阳性、短链状或成对排列的球菌,在血琼脂培养基上为灰白色、α溶血、半透明、圆形、边缘整齐的小菌落。通过16S rRNA基因序列比对,分离菌与粪肠球菌菌株LMG 7937的相似度为99.73%,鉴定为粪肠球菌。分离菌的耐药性强,仅对氨苄西林、青霉素、米诺环素、强力霉素敏感,同时检测到氨基糖苷类耐药基因aac(6')/aph(2″)、ant(6)-I、aph(3')-III、大环内酯类耐药基因ermB、林可酰胺类耐药基因lsa(E),以及心内膜抗原基因efaA和胶原蛋白黏附素基因ace两个毒力基因。致病性试验显示,小鼠在注射高剂量菌液后于24 h内出现死亡,剖检发现脾脏肿胀、肝脏表面有白色纤维素渗出物覆着、肠道出血等,从病变组织中再次分离到粪肠球菌。【结论】成功从病死鸭中分离出1株粪肠球菌,该菌株高剂量可导致小鼠死亡,并携带有5个耐药基因和2个毒力基因,临床治疗可选择氨苄西林和米诺环素等药物。[Objective] Isolation and identification of Enterococcus faecalis was carried out from the dead ducks,and the virulence genes,drug resistance genes and pathogenicity of the isolates were detected,so as to provide reference for understanding the pathogenic mechanism and prevention measures of the bacteria.[Methods] The liver tissues of dead ducks were collected aseptically for the bacteria isolation,purification and stained microscopically.The 16S rRNA gene sequence of the isolated strain was analyzed and the sensitivity to 20 antibiotics was tested.The 11 drug resistance genes and 6 virulence genes of the isolated strains were detected by PCR.The pathogenicity of the strains was detected by Kunming mice challenge test.[Results] The isolated strain was a gram-positive,short-chained or paired-arranged coccus,which showed gray-white,α-hemolytic,translucent,round,neatly edged microcolonies on the blood agar medium.Analysis of 16S rRNA gene sequence indicated that the similarity of the isolated bacteria was 99.73% compared with the Enterococcus faecalis strain LMG 7 937,which was identified as Enterococcus faecalis.The isolated strain was highly resistant to drugs,but sensitive to ampicillin,penicillin,minocycline,doxycycline.Aminoglycoside resistance genes of aac(6')/aph(2″),ant(6)-I,aph(3')-III,macrolide resistance gene of ermB,lincosamide resistance gene of lsa( E) and the virulence genes including the endocardial antigen gene efaA and the collagen adhesion gene ace were all detected from the strain.The pathogenicity test showed that the mice died in 24 hours after injection of the bacterial solution with high dosage.Autopsy revealed swelling of the spleen,white cellulose exudates on the surface of the liver,and intestinal bleeding.Enterococcus faecalis was isolated again from the diseased tissue.[Conclusion] This study successfully isolated a strain of Enterococcus faecalis from dead ducks.The strain can cause mouse death at high doses and carries 5 resistance genes and 2 virulence genes.Ampicillin and minocycl

关 键 词：粪肠球菌 分离鉴定 药敏试验 耐药基因 毒力基因 

分 类 号：S858.32[农业科学—临床兽医学]