【作者】 王瑞；

【导师】 张德礼；

【作者基本信息】 西北农林科技大学 ， 预防兽医学（专业学位）， 2015， 硕士

【摘要】 陕西咸阳某奶牛场一奶牛出现食欲不振,以乳汁分泌量减少,乳房肿胀为主要特征的疾病,初步鉴定为奶牛临床型乳房炎。为了控制此病的蔓延,通过对致病菌分离纯化、形态学观察、生化试验及体外药物敏感性试验,鉴定出一株致病菌命名为HNYM。试验结果如下:1、从患病奶牛乳汁中分离出一株细菌,命名为HNYM株。分离纯化的菌株在血平板上生长良好,有β溶血现象。菌落微小呈针尖状,菌落扁平、边缘整齐、白色、不透明、干燥菌落。革兰染色镜检为阳性长杆菌。2、将细菌的纯培养物进行糖发酵试验,分离菌能发酵葡萄糖、麦芽糖、果糖、乳糖、D-果糖、蕈糖、鼠李糖、D-木糖、树胶醛糖、菊糖产酸,M.R、V-P试验、接触酶试验呈阴性,疑是化脓隐秘杆菌。对消毒剂和β-内酰胺类抗生素较为敏感,对磺胺类药物具有抗性。3、16S rRNA序列与化脓隐秘杆菌属细菌的同源性最高,在92%~99%之间。遗传进化树分析结果表明,HNYM株与化脓隐秘杆菌属在同一大类,最终诊断该奶牛为化脓隐秘杆菌感染。4、小白鼠腹腔注射不同体积菌液,剖检发现心脏、肝脏、肺脏等组织均有明显病变,肌肉注射不同体积菌液,腿部肌肉化脓坏死,后肢瘫痪,对照组健康存活。上述试验结果表面,化脓隐秘杆菌HNYM株对小鼠有致病性,外毒素是其主要致病因子。综上所述,本研究所分离HNYM菌株鉴定为化脓隐秘杆菌,耐药性不强、致病性较强。更多还原

【Abstract】 An infectious disease, mainly characterized by reduction in the breast milk secretion, loss of appetite, breast tenderness, occurred in a dairy farm in Xianyang Shannxi province, were identified as clinical mastitis. For the diagnosis and prevention of the occurrence of disease, by means of isolation and purification of bacteria, morphological observation, biochemical test and drug sensitivity test in vitro, we identified a pathogenic bacteria named HNYM. The results were summarized in the following points:1. A strain of bacteria named HNYM was isolated from diseased cow milk. The strain grow well on blood agar with β hemolytic phenomena. Colonies were tiny, needle-shaped, flat, neat edge, white, opacity and dry, stain showed positive and bacilli.2. Making carbohydrate fermentation test with the bacterial, it could ferment glucose, maltose, fructose, lactose, D-fructose, mushroom sugar, rhamnose, D-xylose, arabinose, synanthrin to product acid. M.R, V-P test, contact enzyme test were negative, suspected it was trueperalla pyogenes. Sensitive to disinfectant and beta lactam antibiotics, resistant to sulfa drugs.3. The 16 SrRNA sequence was highly homology with the trueperalla pyogenes, between 92% to 99%. The analysis results of phylogenetic tree was showed that the HNYM strains at the same type with trueperalla pyogenes, The cow was finally diagnosed as infection of trueperalla pyogenes.4. Mice were injected with different volume of bacterial, autopsy was found that heart, liver, lungs and other tissues had significant pathological changes. By intramuscular injection of the mice with different volume of bacterial and found that the leg muscles was festered and necrosised, hind legs was paralyzed. The control groups were alive. The experimental results showed that the HNYM strains of trueperalla pyogenes were pathogenic to mice and the main pathogenic factor is external toxin.In conclusion, the research separated the HNYM strain and identified it as trueperalla pyogenes, drug resistance is not strong but with high pathogenicity.更多还原