Isolation,Drug Sensitivity Test and Construction of Prokaryotic Expression Vector of Virulence Genes of Enterococcus from Dairy Cow with Mastitis in Gansu Province     

SHEN Yulong  MEN Qianyun  CHEN Tingting  LI Zongshuai  LI Haijiang  YANG Yang  ZHANG Yong  ZHAO Xingxu 《中国畜牧兽医》2007,47(10):3389-3400

The aim of this study was to isolate Enterococcus in clinical dairy cow mastitis,detect its drug resistance and virulence genes,a total of 93 milk samples were collected from 41 dairy cosw with clinical mastitis in eastern,central and western regions of Gansu province,and then construct a prokaryotic expression vector for virulence genes.This experiment used selective medium to isolate and purify bacteria.16S rRNA and biochemical experiments combined method to identify the isolated strains.16 antibiotics were selected for drug sensitivity test,and conventional PCR method was used to detect the carrying of 11 virulence genes.Finally,the detected virulence genes with immunogenicity were selected for the construction of prokaryotic expression vectors.The separation and identification results showed that 18 strains of Enterococcus were isolated and identified from the 93 milk samples,which were divided into 9 species.Drug susceptibility results showed that most of the isolates were multiple resistant to bacteria,accounting for 88.89%.No vancomycin-resistant Enterococcus was found,vancomycin sensitivity rate was 94.12%,and all isolates were resistant to at least one antibiotic.Virulence gene test results demonstrated that 11 virulence genes were detected,the detection rate of cob gene (44.44%) was the highest,the detection rates of efaA,hyl,ccf and esp genes were 33.33%,27.78%,27.78% and 22.22% respectively,the detection rates of Asa1,cylA,EF3314 and gelE genes were all 16.67%,while Ace and cylM genes had the lowest detection rate (11.11%).The virulence genes combination was different due to different strains.Ace and gelE genes with immunogenicity were selected and the prokaryotic expression vector pET32a-Ace and pET32a-gelE were successfully constructed.The results provided basic data and biological materials for subsequent mapping of regional epidemiology of cow mastitis in three regions and preparation of corresponding antibodies and subunit vaccines.  相似文献   

豆腐(豆浆)中屎肠球菌生长的温度预测模型   总被引：12，自引：0，他引：12       下载免费PDF全文

李博  李里特  辰巳英三  李再贵 《中国农业大学学报》2003,8(2):49-54

采用预测食品微生物学的方法研究了豆腐(豆浆)中主要腐败微生物屎肠球菌的生长规律，建立了屎肠球菌在豆浆培养基中的初级和二级预测模型，研究了0—55℃屎肠球菌的生长曲线。结果表明，在适温阶段屎肠球菌的生长曲线呈典型的S形，适合用Gompertz模型拟合；当温度接近最低生长温度和最高生长温度时，适合用线性回归方程拟合。屎肠球菌在立浆中生长的温度模型符合Ratkowsky3式。根据预测模型，屎肠球菌的最低生长温度为4．8℃，最高生长温度为54.6℃，最适生长温度为4l℃。对模型进行了验证。  相似文献   

猪源降胆固醇肠球菌的分离鉴定     

崔德凤  杨桂梅  贾琳  毛伟立  付立伟  李焕荣  阮文科  汪明  张永红 《北京农学院学报》2009,24(4):32-34,41

为了筛选益生菌并评价其对血清胆固醇的降解作用,从健康猪胃肠道分离鉴定12株肠球菌,进行体外降胆固醇,对酸和胆盐的耐受性试验,结果表明：分离菌均具有体外降解血清胆固醇的作用,降解率为16．67～48．00％,对pH3．0和0．4％的胆盐具有抵抗力,综合评价E1和E7可以作为降胆固醇的备选益生菌株。  相似文献   

猪源肠球菌两种致病基因和表型的检测     

刘磊  崔保安  王亚宾  程金平  王中明  郭敏 《勤云标准版测试》2009,29(1)

为调查53株猪源肠球菌2种致病基因和2种表型的分布,应用聚合酶链反应检测53株肠球菌的2种致病基因,用50ml/L兔血平板和30g/L明胶平板检测β溶血和明胶溶解表型。检测结果表明,溶血素激活基因(cylA)明胶酶基因(gelE)为猪源肠球菌的主要致病基因;粪肠球菌2种致病基因和2种表型的检出率高于屎肠球菌;来源于新鲜猪肉中的粪肠球菌存在一定的致病力,提示注意食品卫生安全;在新鲜猪肉中检测到2株鸟肠球菌,基因型和表型检测说明其存在较弱毒力。  相似文献   

乳酸菌株植物乳杆菌和粪链球菌对肉鸡免疫性能的影响   总被引：6，自引：0，他引：6  

杭柏林  胡建和  刘丽艳  刘保国  王丽荣  王宪文  王三虎 《广东农业科学》2008,(11):80-83

将植物乳杆菌和粪链球菌2株乳酸菌分别添加到肉鸡饲料中,通过检测免疫器官指数、胸腺和脾脏的T细胞百分数、白细胞吞噬率、红细胞花环率、血清中新城疫(ND)血凝抑制(HI)抗体效价等指标,探讨了乳酸菌对肉鸡免疫性能的影响.结果表明,2株乳酸菌均能够促进肉鸡胸腺、脾脏和法氏囊的发育,增强白细胞的吞噬功能,增加胸腺和脾脏中的T细胞数,提高E-C3bR和E-ICR的花环形成率,以及提高机体产生ND疫苗HI抗体的水平.  相似文献   

粪肠球菌毒力因子gelE研究进展          下载免费PDF全文

孟庆君  高原  吕娜 《农学学报》2015,5(2):79-82

粪肠球菌与多种感染相关,明胶酶是其主要毒力因子之一,它影响粪肠球菌毒力,与粪肠球菌生物被膜形成有关。现对gelE在生物被膜形成中的作用进行综述。  相似文献   

微囊包被处理屎肠球菌制粒耐受性的评价     

刘文彬  马秋刚  邓程君  魏秀莲  张建云  计成 《中国农业科学》2012,45(6):1169-1175

【目的】通过对比微囊包被与普通粉末状屎肠球菌在不同热处理条件下的活菌数,观察微囊包被处理对屎肠球菌在高温环境下的保护效果,并通过实验室模拟热处理试验,评价微囊包被屎肠球菌制粒时的耐受性。【方法】热处理方法为烘箱干热法,温度分别为65和85℃,热处理时间分别为5、10、15、30及60 min;仔猪饲料中添加0.01%的微囊包被屎肠球菌制剂,分别在55和65℃进行制粒。检测经热处理和制粒后屎肠球菌的活菌数,计算存活率。【结果】微囊包被型屎肠球菌经65℃加热60 min,其活菌数显著高于同条件下的普通粉末型（P=0.037）;而在85℃条件下加热30或60 min,微囊包被型的活菌数极显著高于普通粉末型（P=0.002）。与直接加热活菌制剂相比,将其添加到仔猪配合饲料中后进行相同热处理其存活率显著降低（P＜0.05）;制粒的过程对微囊包被屎肠球菌的破坏作用,要远大于实验室条件下单纯的温度破坏;饲料在55℃制粒时屎肠球菌的存活率与饲料在65℃加热28 min或85℃条件下加热11 min相当;而在65℃制粒时屎肠球菌的存活率,相当于饲料在65℃加热48 min或85℃条件下加热23 min。【结论】微囊包被处理可以在一定程度上保护屎肠球菌的活性,提高其对高温和制粒的耐受性;直接对屎肠球菌活菌制剂进行干热处理时的存活率不能准确反映其制粒时的稳定性,但可以采用将微囊包被屎肠球菌添加到饲料中进行实验室模拟热处理试验,估测制粒过程中屎肠球菌的耐受性。  相似文献   

仔猪关节炎粪肠球菌生物学特性研究     

王亚宾  张祥  胡清林  孟振北  陈丽颖  陈小丽  崔保安 《河南农业大学学报》2011,45(2):183-187

从病猪肿大的跗关节中分离了1株疑似肠球菌菌株,经过常规方法进行染色特性、培养特性观察以及敏感性和致病试验,利用Vitek-32全自动细菌鉴定系统进行生化特定,并用PCR方法扩增分离株的16S rRNA基因克隆测序,与GenBank上登录的相关菌株及3个粪肠球菌标准菌株进行16S rRNA序列比较、同源性分析并构建系统发...  相似文献   

屎肠球菌T013复合制剂饲喂生长猪的效果研究     

华均超  张邦辉  周明  李金友 《中国畜牧兽医》2012,39(10):112-116

试验旨在研究日粮中添加屎肠球菌T013复合制剂对生长猪的生产性能、粪便微生物、环境指标及血清指标的影响。选用体重在(31.75±3.78)kg的杜×长×大三元杂交仔猪120头,随机分成对照组(基础日粮)、试验Ⅰ组(基础日粮中添加3%屎肠球菌T013复合制剂)和试验Ⅱ组(基础日粮中添加6%屎肠球菌T013复合制剂),每组4个重复,每个重复10头猪,试验期为28 d。结果表明,屎肠球菌T013复合制剂能增加生长猪日采食量和日增重,降低料重比,但差异不显著(P＞0.05),并且能显著减少腹泻率(P＜0.05);试验Ⅱ组能够极显著降低粪便pH和减少大肠杆菌数量,增加乳酸菌数量(P＜0.01);试验组均能够极显著的减少NH₃的排放(P＜0.01);试验Ⅱ组能够显著增加血清IgG含量和减少尿素氮含量(P＜0.05),对总蛋白、白蛋白、白蛋白/球蛋白和葡萄糖的含量无显著影响(P＞0.05)。因此,屎肠球菌T013复合制剂能够降低生长猪的腹泻率,改善肠道微生态环境,减少NH₃ 的排放,增强猪的免疫能力。  相似文献   

Isolation,Identification and Drug Resistance Analysis of Pathogenic Enterococcus feacium of Sheep     

LIU Yong-an  LI Xue-rui  ZHOU Jian-hua  MA Li-na  LIU Yong-sheng 《中国畜牧兽医》2017,44(2):530-537

To further identify the pathogenic strains and analyze their antibiotic resistance, the methods of pathogen isolating, the methods of Gram staining, biochemical tests and 16S rRNA PCR amplification, virulence tests, drug sensitive tests, virulence genes and resistance genes PCR amplification were used. The results showed that the strain was Gram-positive and revealed positive after reacting with 6.5% NaCl, melibiose, sucrose and etc., while revealed negative reactions with VP, hippurate, arabinose and etc.. It showed 100% similarity with Enterococcus feacium 16S rRNA gene sequence in GenBank after PCR amplification of 16S rRNA gene and BLAST alignment. It was found severe pathogenicity after virulence tests in mice. The strain was highly resistant to oxacillin, penicillin G of β-lactam antibiotics and norfloxacin, ciprofloxacin, levofloxacin of quinolones antibiotics and tetracycline, while was sensitive to antibiotics of erythromycin, vancomycin and clindamycin. It revealed that virulence factor genes Asal, cylA, acm and resistance genes TetM, ant(6)-Ⅰ, aac(6')-aph (2"), ermB showed positive. The results showed that the bacteria was Enterococcus feacium, it had a strong pathogenicity and severe drug resistance, which might be related to the highly positive rates of virulence genes and drug resistance genes.  相似文献