猪源产肠毒素大肠杆菌疫苗的研究进展

仔猪腹泻是全球集约化猪场的高发疾病之一,给养猪业造成了巨大的经济损失。产肠毒素大肠杆菌(ETEC)是导致新生仔猪和断奶仔猪腹泻的主要致病菌,菌毛黏附素和肠毒素是其重要的致病因子。接种疫苗是仔猪腹泻最有效的防治方法,然而ETEC疫苗有明显的地域局限性和安全性问题。因此,研制安全、高效且适用性广的ETEC疫苗对畜禽养殖业具有重要意义。近年来在ETEC疫苗的研制方面已取得了重大进展,出现多种亚单位疫苗、基因工程疫苗和弱毒疫苗。本文对ETEC的致病机制及相关疫苗的研究进行简要介绍。     

大肠杆菌表达的融合蛋白K88ac-STⅡ的免疫效果

产肠毒素大肠杆菌（enterotoxigenic escherichiacoli，ETEC）是引起幼畜腹泻的病原菌，感染病畜发病快，死亡率高。研究表明，病原菌ETEC的致病过程包括菌毛粘附因子对小肠上皮细胞的粘附和致腹泻毒素的产生，其中，菌毛粘附是其致病的始动因素，毒素是其致病的直接原因。所以，研制针对菌毛和毒素的多价疫苗理论上可以有效地预防幼畜腹泻。据调查，     

大肠杆菌致病因子研究进展

大肠杆菌是重要的肠道菌群,致病性大肠杆菌可引起人畜疾病。多年来,大肠杆菌对畜禽养殖业造成了严重的经济损失,也对人类的健康产生了极大影响,对大肠杆菌致病机制的研究刻不容缓。本文综述了近年来致病性大肠杆菌肠毒素、菌毛黏附素、类志贺毒素、外膜蛋白等多种毒力因子的研究进展。     

大肠杆菌O157和其它产志贺毒素大肠杆菌的毒力因子——粘附素

大肠杆菌O157的致病性已引起全世界公众和微生物学家的关注，而O157的致病因子有很多，本文就大肠杆菌O157可能的粘附素：菌毛、OMP及紧密素在致病中的作用进行综合评价，并对这些因子在其它产志贺毒素大肠杆菌中的出现率及与致病的关系进行分析，以期对大肠杆菌O157的致病机理有一个比较清楚的认识，推动我国对大肠杆菌O157的研究，以填补我国在这方面的相对空白。     

肠道外致病性大肠杆菌外膜蛋白研究进展

肠道外致病性大肠杆菌病(Extraintestinal pathogenic Escherichia coli,ExPEC)是一种常发肠道外疾病,危害人类、动物的健康,也导致禽类产蛋量的下降及肉用动物的上市延迟,严重的则引起死亡。因此,对于肠道外致病性大肠杆菌的致病机制也是许多学者研究的热点,肠道外致病性大肠杆菌致病机理的研究近些年主要集中在脂多糖(LPS)、外膜蛋白(Outer membrane protein,Omp)、菌毛、鞭毛、等毒力因子方面。     

猪源产肠毒素性大肠杆菌主要毒力因子研究进展

产肠毒素性大肠杆菌(enterotoxigenic Escherichia coli,ETEC)是引起婴幼儿和幼畜腹泻的主要细菌性病原,初生幼畜感染后常因剧烈腹泻脱水而死亡。菌毛黏附素和肠毒素是ETEC目前研究最多的2类毒力因子,随着技术手段的不断进步和研究的深入,一些新型毒力因子不断被发现,如鞭毛、非菌毛黏附素、肠聚集性耐热毒素(the enteroaggregative heat-stable toxin1,EAST1)、自转运黏附蛋白、细胞溶血素等。本综述主要针对猪源ETEC的主要毒力因子以及新型毒力的结构功能及致病性进行阐述,为进一步深入探索ETEC的致病机理提供理论基础。     

鸡致病性大肠杆菌Ⅰ型菌毛的研究进展

鸡致病性大肠杆菌Ⅰ型菌毛是鸡大肠杆菌病的重要致病因子.本文对其生物学特性、在感染中的作用、分子生物学等8个不同方面的研究进展做了综述.     

鸡致病性大肠杆菌I型菌毛的研究进展

鸣致病性大肠杆菌I型菌毛是鸡大肠杆菌病的重要致病因子。本文对其生物学特性、在感染中的作用、分子生物学等8个不同方面的研究进展做了综述。     

猪链球菌2型毒力因子及疫苗候选蛋白研究进展

猪链球菌2型（ss2）是一种重要的人兽共患病病原菌,可引起人和猪发生严重疾病。SS2的经典毒力因子有荚膜抗原、溶菌酶释放蛋白、溶血素等。随着研究的深入．又发现了一些与SS2致病性相关的基因和毒力相关元件,以及一些蛋白酶类,这些毒力因子多数具有较好的免疫原性,并在链球菌致病和生长过程中发挥十分重要的作用。通过对一些具有免疫原性的SS2毒力因子蛋白片段进行体外重组表达,有望研制出有效预防SS2感染的基因工程疫苗。     

同位素标记检测卵黄抗体对大肠杆菌的黏附抑制作用

<正>仔猪大肠杆菌性腹泻的主要病原为产肠毒素性大肠杆菌(enterototxigenic Escherichia coli,ETEC)[1,7]。ETEC的致病作用主要由肠毒素和黏附素性菌毛等两类毒力因子共同构成[2],其主要的致病环节是ETEC     

鸡新城疫与大肠杆菌病混合感染的诊治

鸡新城疫是由鸡新城疫病毒引起的一种急性、高度接触性传染病,致死率较高。目前,我国普遍采用以新城疫疫苗接种为主的综合防控措施,能够在很大程度上控制该病的大规模流行。鸡大肠杆菌病是由大肠埃希菌感染引起的传染病,多个血清型的大肠埃希菌是多种动物肠道内的常驻菌,因此其分布极为广泛,致病率也较高,并且多与其他疫病混合感染。通过开展病死鸡的病理变化检查、实验室检验以及分离菌株的药物敏感性试验,对临床接诊的鸡新城疫及大肠杆菌混合感染病例进行诊断并提出综合防控措施,以期为兽医临床2种疾病的防控提供有益参考。     

散养蛋鸡大肠杆菌病防控

蛋鸡大肠杆菌病是由致病性大肠杆菌感染引发的一种常见传染性疾病。大肠杆菌在自然界中广泛存在,属于条件性致病菌,在卫生条件较差、应激因素较多的养殖场发生流行。大肠杆菌病具有发生范围广、感染群体多、传播途径多样的特点,随着鸡年龄下降,发病后表现的死亡率逐渐提升。养殖户在发展蛋鸡养殖产业时由于不科学的用药行为,使大肠杆菌耐药性显著增强,多种药物防控效果变差,给该类疾病防控治疗工作带来很大难度。该文探讨散养蛋鸡大肠杆菌病的防控措施。     

Feline viral respiratory disease: a review with particular reference to its epizootiology and control

The two major causes of feline viral respiratory disease are feline viral rhinotracheitis virus and feline calicivirus. This paper reviews the present state of knowledge concerning these viral agents, the clinical syndromes they produce, their maintenance in the cat population including recent developments in the understanding of their carrier states, and finally the methods by which they spread. The second part of the paper attempts to correlate this information in a section which deals with the practical problems of prevention and control; management factors pertinent to the control of respiratory disease and problems of vaccine development and vaccine use are discussed. A short section on treatment is included.     

Intranasal immunisation with Stx2B-Tir-Stx1B-Zot protein leads to decreased shedding in goats after challenge with Escherichia coli O157:H7

Ruminants are an important reservoir of Escherichia coli O157:H7. To reduce E coli O157:H7 excretion by these animals could play a key role in prevention and control of human infections. In the present study, the authors used 12 three-month-old goats to evaluate the efficacy of intranasal administration of the Stx2B-Tir-Stx1B-Zot protein. These goats were inoculated on days 0 and 21 and infected with 10(10) colony-forming units (cfu) of E coli O157:H7 by oral inoculation on day 36. Faecal shedding was monitored daily for two weeks. All of six goats immunised with recombinant protein elicited significant Stx2b-Tir-Stx1b-Zot-specific serum IgG antibodies, and three of them also showed production of antigen-specific IgA in faeces. The immunised goats showed much less shedding of E coli O157:H7 after challenge. These results demonstrate the potential for the use of Stx2B-Tir-Stx1B-Zot protein in mucosal vaccine formulations to prevent colonisation and shedding of E coli O157:H7 in goats.     

仔猪白痢的诊断与防治策略

仔猪白痢是猪场的常发病和多发病,病死率虽低,但严重影响仔猪生长发育,易形成僵猪,给猪场造成较大经济损失。文章从仔猪白痢的病原学特点流行病学、临床症状、病理变化、实验室诊断、防治等方面分别展开论述,首先阐述了大肠杆菌的形态染色、生长需要、菌落形态等;随后对仔猪白痢的流行病学、临床症状、病理变化、3种实验室诊断方法及优缺点进行论述;重点阐述了仔猪大肠杆菌病疫苗的应用、抗生素与中药的防治等,以期对猪场控制该病提供借鉴。     

蛋鸡大肠杆菌感染症状特点与防治

蛋鸡养殖中大肠杆菌感染是一种常见疾病,主要是由于致病性大肠杆菌导致的一种接触传染性疾病,通常由于致病性大肠杆菌入侵蛋鸡不同的组织部位,造成的疾病症状有所不同。蛋雏鸡在感染了致病性大肠杆菌后容易出现急性败血症的情况,成年蛋鸡会出现关节滑膜炎症、腹腔膜炎症及输卵管炎症等。现阶段蛋鸡养殖中致病性大肠杆菌感染疾病的防治措施主要是疫苗免疫和药物治疗的防治,但还是存在一定的缺陷,导致部分蛋鸡出现大肠杆菌感染的情况。该文将对蛋鸡养殖中大肠杆菌感染疾病的流行病学特点、临床症状及相关的防治措施进行介绍。     

A systemic vaccine based on Escherichia coli O157:H7 bacterial ghosts (BGs) reduces the excretion of E. coli O157:H7 in calves

Cattle are the main reservoir of enterohemorrhagic Escherichia coli O157:H7, a bacterium that, in humans, causes hemorrhagic colitis and hemolytic uremic syndrome (HUS), a life-threatening disease, especially in children and older people. Therefore, the development of vaccines preventing colonization of cattle by E. coli O157:H7 could be a main tool for an HUS control program. In the present study, we evaluated bacterial ghosts (BGs) of E. coli O157:H7 as an experimental vaccine against this pathogen. BGs are empty envelopes of Gram-negative bacteria, which retain the morphological surface make-up of their living counterparts and are produced by controlled expression of the cloned protein E, which causes loss of all the cytoplasm content. In this work, E. coli O157:H7 BGs were used for subcutaneous immunization of calves. The vaccinated animals elicited significant levels of BG-specific IgG but not IgA antibodies in serum. Low levels of IgA and IgG antibodies against BGs were detected in saliva from vaccinated animals. Following oral challenge with E. coli O157:H7, a significant reduction in both the duration and total bacterial shedding was observed in vaccinated calves compared to the nonimmunized group. We demonstrated that systemic vaccination with E. coli O157 BGs provides protection in a bovine experimental model. Further research is needed to reach a higher mucosal immune response leading to an optimal vaccine.     

Avian pathogenic Escherichia coli (APEC).

Avian pathogenic Escherichia coli (APEC) cause aerosacculitis, polyserositis, septicemia and other mainly extraintestinal diseases in chickens, turkeys and other avian species. APEC are found in the intestinal microflora of healthy birds and most of the diseases associated with them are secondary to environmental and host predisposing factors. APEC isolates commonly belong to certain serogroups, O1, O2 and O78, and to a restricted number of clones. Several experimental models have been developed, permitting a more reliable evaluation of the pathogenicity of E. coli for chickens and turkeys. Hence, virulence factors identified on APEC are adhesins such as the F1 and P fimbriae, and curli, the aerobactin iron sequestering system, K1 capsule, temperature-sensitive hemagglutinin (Tsh), resistance to the bactericidal effects of serum and cytotoxic effects. Experimental infection studies have shown that the air-exchange regions of the lung and the airsacs are important sites of entry of E. coli into the bloodstream of birds during the initial stages of infection and that resistance to phagocytosis may be an important mechanism in the development of the disease. They have also demonstrated that F1 fimbriae are expressed in the respiratory tract, whereas P fimbriae are expressed in the internal organs of infected chickens. The role of these fimbrial adhesins in the development of disease is not yet, however, fully understood. The more recent use of genetic approaches for the identification of new virulence factors will greatly enhance our knowledge of APEC pathogenic mechanisms. Diagnosis of APEC infections is based on the clinical picture, lesions and isolation of E. coli. This may be strengthened by serotyping and identification of virulence factors using immunological or molecular methods such as DNA probes and PCR. Approaches for the prevention and control of APEC infections include the control of environmental contamination and environmental parameters such as humidity and ventilation. Antibiotherapy is widely used, although APEC are frequently resistant to a wide range of antibiotics. Vaccines containing killed or attenuated virulent bacteria protect against infection with the homologous strain but are less efficient against heterologous strains. Hence, vaccination for colibacillosis is not widely practised because of the large variety of serogroups involved in field outbreaks.     

产肠毒素性大肠杆菌K99菌毛蛋白抗原基因的克隆与表达

应用PCR从产肠毒素性大肠杆菌（ETEC）中扩增出不含信号肽序列的K99菌毛蛋白基因片段，克隆测序后，将该片段连接到E.coli表达载体pET28a( )中，转化E.coli表达菌株BL21（DE3），筛选得到可诱导表达K99抗原的工程菌株。经IPTG诱导，分离纯化K99重组蛋白，以其免疫新西兰大白兔，获得重组蛋白的兔抗血清；免疫印迹分析表明，此重组蛋白制备的抗血清能与标准的K99强毒株姓明显的抗原抗体反应。     

关中奶山羊乳房炎灭活菌苗的制备及其免疫效果测定

对自制乳房炎疫苗免疫后的抗体效价进行评估.用甲醛37℃过夜灭活大肠埃希菌、葡萄球菌,分别制备蜂胶灭活疫苗、转移因子灭活苗及无佐剂疫苗,接种泌乳期奶山羊后,分别在不同时间采集免疫羊的血清和乳汁,ELISA测定血清大肠埃希菌和葡萄球菌的抗体效价.研究结果显示,大肠埃希菌和葡萄球菌经甲醛灭活彻底;与免疫前相比,血清和乳汁中的...