【作者】 张振苹；

【导师】 崔言顺；

【作者基本信息】 山东农业大学 ， 兽医， 2010， 硕士

【摘要】 猪链球菌(Streptococcus suis, SS)是危害现代养猪业的一种重要人兽共患病病原,该菌血清型多、抗原结构复杂,在临床上可呈现不同的特征,如败血症、脑膜炎、心内膜炎、肺炎、关节炎等,还常常与其他疾病合并感染,发病率和死亡率较高。由于目前对猪链球菌病的发生规律、病原特性以及防治措施还不是十分清楚,单纯靠药物又不能有效地控制该病的发生和蔓延。2005—2009年,黄河口地区的规模化养猪场所饲养的猪有不同程度的猪链球菌病发生。该试验从病原学着手研究,在对黄河口地区分离的猪链球菌菌株进行培养、鉴定基础上,建立PCR方法对其进行毒力基因检测,以便为该病的免疫防治提供理论依据。本课题分为两个部分进行研究。1黄河口地区致病性猪链球菌的分离鉴定及耐药性状况调查收集2005年—2009年黄河口地区规模化养猪场疑似猪链球菌患病猪,根据临床诊断、病理学观察,结合病原的分离培养与鉴定等,确诊为猪链球菌病。通过革兰氏染色镜检、生化试验、药敏试验,对临床分离的猪源链球菌进行流行病学的初步研究。从该地区的发病猪分离到的15株猪源链球菌,其形态、染色、培养特征及理化特性符合猪链球菌的特点,药敏试验结果显示,黄河口地区猪链球菌仅对氨苄西林、阿米卡星、头孢噻肟、头孢唑啉敏感,而对其他常规药物已产生了不同程度的耐药性。2猪链球菌两种主要毒力因子的双重PCR检测根据猪链球菌两种主要毒力因子基因Sly和MRP的基因序列,设计和合成了2对特异性引物,通过体系和条件优化,建立双重PCR检测方法,对15株背景明确的猪链球菌保存菌株进行检测。结果显示,Sly检出率为4/15,MRP检出率为2/15,阳性、阴性对照均成立。分析结果表明该双重PCR检测方法,特异性和敏感性较好,可用于快速诊断以及猪链球菌相关毒力因子的分子流行病学调查。更多还原

【Abstract】 Streptococcus suis is one of the primary diseases that threaten modern pig industry. Because of the great varity of streptothrix serum type and the complex structure of antigen, it presents different clinical symptom, such as septicemia, meningoencephalitis, endocarditis, pneumonitis, porodenia arthritis and so on. Now we are not very clear with occurrence regulation and the original characteristic of streptococcosis disease, and its infection and spread can not be effectively controlled simply by medicines. There occurred swine streptococcosis at different degree in large-scale piggery in Huanghe River Mouth Area from 2005 to 2009. In order to provide theoretical basis for immune protection of Swine Streptococcosis, we study it from pathogen, on the foundation of culture and identification of Streptococcus suis from Huanghe River Mouth Area, PCR method was established to detecte the virulence gen. Three experiments were carried out to obtain the study.1 Isolation and identification and investigation on serotypes and drug resistance of pathogenic Streptococcus suis of Huanghe River Mouth Area. Molecular epidemiology of Streptococcus suis isolates were primarily studied through morphology, gramstain, biochemical test, drug sensitivity test. Fifteen Streptococcus suis strains were isolated from infected pigs of different areas in Huanghe River Mouth Area, which morphology, dyeing, cultural characteristics and physicochemical properties are coincidence with Streptococcus suis. The drug sensitivity test indicated that Huanghe River isolates are only sensitive to ampicillin, amikacin, cefotaxime, cefazolin, and have produced drug resistance at different degree to other routine drug.2 Detection of virulence-associated factors of Streptococcus suis by duplex PCR assay. Design and synthesis two distinct primers based on the main virulence factors Sly and MRP of Streptococcus suis, establish a duplex PCR detection method by optimizing the condition and system, the method was used to analyse the experimental strains and control strains. With the identified 15 Streptococcus suis strains, the positive detection rates of Sly, MRP were 4/15 , 2/15 , there were no specific amplification products in negative control strains. The results demonstrated that duplex PCR was a highly specific and sensitive diagnostic tool for the detection of virulence-associated factors of Streptococcus suis.更多还原