鸡大肠杆菌病的病原分离鉴定与药敏试验

无菌采集山西某地临床上疑似为鸡大肠杆菌病的6只病死鸡的心、肝、脾,进行细菌学检验,鉴定出6株鸡大肠杆菌。将分离菌株分别接种试验动物,对小白鼠致死率达83.33%。药敏试验结果表明,6个菌株表现出相似的药物敏感性,对庆大霉素、卡那霉素、诺氟沙星敏感,对土霉素、双黄连、多西环素、板蓝根、泰乐菌素耐药。     

鸡大肠杆菌病病原菌的分离鉴定

无菌采取山西省长治市蛋鸡场送检的疑似大肠杆菌病的病死鸡的心血、肝、脾、肾,进行病原菌的分离、鉴定、生化试验和动物试验,结果显示引起该鸡场鸡只发病的病原为大肠杆菌,并且该菌对小白鼠和鸡有较强的致病力。     

鸡致病性大肠杆菌油乳剂灭活苗的制备

从太谷某鸡场分离到疑似鸡大肠杆菌2株,经分离培养鉴定确认为大肠杆菌,血清型分别是O2和O78,将分离菌株经过致病性试验、增菌培养,制备了大肠杆菌灭活苗,经试验证明,本疫苗安全、有效。每只鸡免疫接种0.6mL以上临床无不良反应,对地方性鸡大肠杆菌病有较好的预防作用。     

鸡致病性大肠杆菌分离鉴定及药敏试验

以干海乡一生态鸡鸡苗场中分离得到的鸡致病性大肠杆菌病原菌为试验对象,采用细菌形态学观察以及生化试验、动物试验和血清学试验等方法,表明所分离到的5个菌株为致病性大肠杆菌。用氨苄青霉素、庆大霉素、四环素、磷霉素、新霉素、土霉素、链霉素、红霉素、氟苯尼考、氧氟沙星、头孢曲松、阿莫西林等12种药物对5个不同菌株进行药敏试验比较。结果表明:5个菌株均对新霉素、阿莫西林、头孢曲松和磷霉素高度敏感。对庆大霉素、四环素、土霉素等抗菌药物耐药性极强。     

鸡大肠杆菌的分离与鉴定

试验对鸡大肠杆菌进行分离鉴定,分离出的56株大肠杆菌中,共鉴定出47株菌株的血清型,分属O1、O2、O5、O35、O78、O1116种不同O抗原血清型,占分离菌株的83.9%。其中O1、O2、O78、O111最常见,占已定型菌株的83%。     

鸡大肠杆菌抗药性调查

对2000-2002年分离鉴定的47株鸡大肠杆菌进行了抗药性调查。多数分离菌株对多数抗菌药物具有耐药性;多数抗菌药物的抗菌效力不佳;优选出丁胺卡那霉素、诺氟沙星、磷霉素、庆大霉素、恩诺沙星、环丙沙星6种效果较好的药物;分析了抗药菌株产生的原因;建议治疗大肠杆菌病时先行药敏试验;建议少用或不用药物添加剂,并规范化用药,以提高疗效防止抗药菌株产生。     

新疆昌吉地区鸡大肠杆菌部分菌株分离鉴定及防治研究

从新疆昌吉州地区10个发生疑似大肠杆菌病的商品肉鸡场，无菌采取病鸡、死鸡的心血、肝、脾、肺、肾等组织进行病原菌的分离培养，经过培养特性、形态、染色特性和生化试验，鉴定出21株大肠杆菌，分离株对7日龄雏鸡均具有致病性。从21株致病性大肠杆菌中共鉴定出8种血清型，分别为O1、O3、O6、O36、O88和O103。其中O1、O2和O78为优势血清型，占分离菌株的77．39％。采用13种常用抗菌药物进行药敏试验，四种药物敏感率在90％以上。但21个分离菌株均具有多重抗药性，至少可以抵抗6种以上抗攻药物的杀菌或抑菌作用，而且同一血清型的菌株其药物的敏感性也不同。在药敏试验基础上，选用敏感药物采用不同方案对5个发生大肠杆菌病的鸡场进行了临床治疗试验，取得了良好的使用效果，治愈率达到94％以上。为建立该地区鸡大肠杆菌病的药物防治模式奠定了基础。     

新疆昌吉地区鸡大肠杆菌部分菌株分离鉴定及防治研究

从新疆昌吉州地区10个发生疑似大肠杆菌病的商品肉鸡场,无菌采取病鸡、死鸡的心血、肝、脾、肺、肾等组织进行病原菌的分离培养,经过培养特性、形态、染色特性和生化试验,鉴定出21株大肠杆菌,分离株对7日龄雏鸡均具有致病性。从21株致病性大肠杆菌中共鉴定出8种血清型,分别为O1、O2、O6、O26、O36、O78、O88和O103。其中O1、O2和O78为优势血清型,占分离菌株的77.39%。采用13种常用抗菌药物进行药敏试验,四种药物敏感率在90%以上。但21个分离菌株均具有多重抗药性,至少可以抵抗6种以上抗菌药物的杀菌或抑菌作用,而且同一血清型的菌株其药物的敏感性也不同。在药敏试验基础上,选用敏感药物采用不同方案对5个发生大肠杆菌病的鸡场进行了临床治疗试验,取得了良好的使用效果,治愈率达到94%以上。为建立该地区鸡大肠杆菌病的药物防治模式奠定了基础。     

鸡大肠杆菌病发病原因和防治措施

随着养殖业的集约化生产,鸡大肠杆菌病越来越成为危害养鸡业的重大危害。文章综述了鸡场大肠杆菌病发病原因、流行病学特点、临床症状和病理变化,介绍分离菌株做药敏试验选择高敏药物的结果,为综合的防治措施提供参考。     

泰州地区禽源性大肠杆菌的分离与鉴定

为摸清泰州地区禽大肠杆菌的流行情况及其耐药性,我们于2005年初至4月间,从泰州地区的鸡场、鸭场具有典型大肠杆菌病病变的病死鸡、鸭体内分离到14株大肠杆菌,进行药物敏感性试验,结果显示14个菌株对壮观霉素、阿米卡星高度敏感。血清型鉴定结果显示其O血清型包括O 1、O 2、O 78、O 107。这些菌株均为高致病力毒株。     

Microbiological study results (bacteriology and electron microscopy) of diarrhea in dog whelps

Bacteriological examinations of 159 faeces and intestinal contents of dogs with diarrhoea revealed E. coli in 157 specimens. 73 of these samples contained non haemolytic strains, 18 haemolytic isolates, and 66 haemolytic, as well as non haemolytic strains. Klebsiella sp. and Staphylococcus aureus were found in 9 cases, and Salmonella sp. (group B) was isolated once only. By electron microscopy parvovirus could be detected in 19 samples. Ten were positive for coronavirus and one for rotavirus. Morphologically not finally identified coronavirus like and picornavirus like particles were found in 3 cases, respectively. A significant relationship between the occurrence of virus infections and the isolation of certain bacteria species was not found. In 45 E. coli strains virulence factors, such as the heat labile enterotoxin (LT) and the verotoxin (VT), could not be detected, but 31 of these isolates showed different haemagglutination patterns which were still present by 14 of them in the presence of mannose (mannose resistant haemagglutination, MR-HA). These MR-HA inducing E. coli isolates were present more often in parvovirus positive samples (in 6 of 10) than they could be detected in parvovirus negative ones (in 8 of 35), implicating a potential pathogenic role of these E. coli strains for the parvovirus enteritis of dogs.     

甘露寡糖对断奶仔猪肠道菌群的影响

选取28日龄断奶的三元[杜×(大×长)]杂交仔猪96头,平均体重为(7.46±0.38)kg,按体重和性别随机分为4个处理组,每个处理组3个重复,每个重复8头仔猪,公母各半。第一个处理组为空白组,第二、三、四个处理组在相同的基础日粮中分别添加0.1%、0.2%和0.4%的甘露寡糖,研究甘露寡糖对断奶仔猪肠道菌群的影响。结果表明:(1)各实验组肠道大肠杆菌的浓度极显著低于对照组;(2)第三组和第四组其结肠、盲肠和直肠中双歧杆菌增殖显著。第二组中只有结肠中双歧杆菌显著高于对照组,但盲肠和直肠中双歧杆菌增殖不明显;(3)各个处理组肠道中乳酸杆菌的浓度与对照组相比差异不显著。     

对虾白斑综合征病毒VP28酵母表面展示

以pYD1为载体,制备以酒精酵母为载体的基因工程免疫制剂。参照GenBank中对虾白斑综合征病毒VP28基因序列设计引物,PCR扩增得到预期长度的产物,双酶切插入用于酒精酵母表面展示的穿梭质粒载体pYD1,转化大肠杆菌TOP10,提取阳性质粒转化酒精酵母菌株EBY100,诱导表达后,用免疫荧光检测外源蛋白的表达。结果获得VP28酵母表面展示菌,测得最佳诱导时间为36～48h。以此展示酵母活细胞分设两个浓度组,腹腔注射螯虾,检测其毒性。结果表明,此重组酵母对螯虾是安全的,该研究为下一步对虾用活载体免疫制剂效果的研究奠定了基础。     

斑点叉尾鮰病毒“自杀性”DNA疫苗的构建及其体外表达检测

根据CCVORF6基因序列,设计合适的引物,扩增ORF6基因,分别将其克隆到自杀性DNA疫苗载体pS-FV与常规DNA疫苗载体pcDNA3.1(+)中,转化感受态细胞DH5α后提取质粒,构建斑点叉尾鮰(Ictalurus punc-tatus)自杀性DNA疫苗ps-ORF6与常规DNA疫苗pcd-ORF6,利用转化后的大肠杆菌菌液为模板进行PCR扩增、提取质粒酶切鉴定以及序列测定等方法证实重组质粒构建正确。将重组质粒转染人胚肾细胞(293T),间接免疫荧光试验表明ORF6均获得表达,但自杀性DNA疫苗的表达效果不如常规DNA疫苗,该研究为这2种疫苗进一步的鱼体试验奠定了基础。     

鸡抗鸭源大肠杆菌卵黄抗体的研制

用鸭源大肠杆菌125号菌株制成的灭活油佐剂苗、蜂胶苗及无佐剂菌苗作为免疫原,免疫经产蛋鸡,定期收集鸡蛋,用氯仿提取卵黄抗体,采用试管凝集法检测抗体效价。结果表明:油佐剂灭活苗的抗体维持时间较长,在免疫后60d还能保持较高水平,其峰值达到1∶24。蜂胶灭活疫苗的抗体产生速度比较快,消失也较快,其峰值达到1∶12,40d后抗体基本上消失。不加佐剂的灭活菌苗抗体产生速度较快,10d达到峰值1∶16,然后呈逐渐下降趋势,免疫40d后波动较小。结果,油佐剂灭活菌苗免疫后产生的抗体效价及持续时间高于无佐剂灭活苗和蜂胶苗的抗体效价。     

84株仔猪黄、白痢E.coli的体外药敏试验

从四川省不同规模化猪场临诊发生典型仔猪黄、白痢猪只的肛试粪样及死亡猪只的心血和肝脏中分离出致病性大肠杆菌８４株。用１２种常用抗菌药物对分离菌株进行了体外药敏测定，结果表明：大肠杆菌存在广泛的耐药性，以多重耐药性为主。庆大霉素、链霉素、痢特灵和喹诺酮类（环丙沙星、蒽诺沙星、诺氟沙星）等药物较为敏感。药敏试验结果为规模化猪场合理用药提供了科学依据     

Clinical experience with kennel-specific E. coli oral vaccines in dogs

Kennel-specific oral E. coli vaccines were tested for efficacy and side effects at breeding and boarding kennels with severe diarrhoea problems. Oral vaccines contained heat inactivated E. coli bacteria from specific kennels and were given once daily for 14 days. Oral vaccines were administered directly orally to puppies while for adult dogs vaccines were mixed with daily food rations. In breeding kennels with 4 to 10 week old puppies suffering from non-fatal diarrhoea, the oral immunization led to a decrease in morbidity from 86.5% to 0%. In kennels with some cases of fatal diarrhoea the rate of morbidity decreased from 45% to 21% and the mortality rate from 25% to 10.3% after using the vaccination. By vaccinating adult dogs in boarding kennels the morbidity rate dropped from 83.5% to 6.5% and the mortality rate from 4.1% to 0.5%. The kennel specific oral E. coli vaccine was found to be free of side effects. No adverse effects were observed in either puppies or adult dogs.     

草鱼IFNa和IFNd重组蛋白表达、纯化及单克隆抗体制备

为系统研究草鱼I型干扰素的合成、分泌和免疫功能,本研究在大肠杆菌中表达并提纯了草鱼IFNa（CiIFNa）和IFNd（CiIFNd）重组蛋白。将CiIFNa和CiIFNd成熟肽分别克隆到pET-21d或pEHISTEVb表达载体上,并转化到大肠杆菌中;IPTG诱导表达得到CiIFNa和CiIFNd成熟肽的包涵体,经过盐酸胍变性、蛋白复性和浓缩后,利用AKTA分子筛层析获得了纯度较高的重组蛋白。用重组蛋白免疫小鼠,通过PEG法诱导得到杂交瘤细胞;将稳定分泌抗体的阳性细胞株的细胞悬液注射入小鼠腹腔,制备腹水抗体并进行纯化。本研究纯化了草鱼CiIFNa和CiIFNd各2株抗体,并采用SDS-PAGE、ELISA、Western blot和免疫荧光法对其进行了较全面的鉴定。研究结果表明CiIFNa和CiIFNd单克隆抗体特异性好、效价高,能够特异识别在大肠杆菌和真核细胞中表达的重组蛋白,且不存在CiIFNa和CiIFNd分子间的交叉识别。本研究制备的单克隆抗体为深入研究草鱼干扰素的细胞来源和蛋白表达规律奠定基础。     

Genotypic and phenotypic characterization of Edwardsiella isolates from different fish species and geographical areas in Asia: Implications for vaccine development

The genus Edwardsiella is one of the major causes of fish diseases globally. Herein, we examined 37 isolates from ten different fish species from India, South Korea and Taiwan to gain insight into their phenotypic and genotypic properties, of which 30 were characterized as E. tarda with phenotypic homology estimated at 85.71% based on API‐20E biochemical tests. Genotyping using 16S rRNA put all isolates together with E. anguillarum, E. hoshinae, E. tarda, E. piscicida and E. ictaluri reference strains in a monophyletic group. In contrast, the gyrB phylogenetic tree clearly separated E. ictaluri, E. tarda and E. hoshinae reference strains from our isolates and put our isolates into two groups with group I being homologous with the E. anguillarum reference strain while group II was homologous with the E. piscicida reference strain. Hence, our findings point to E. piscicida and E. anguillarum as species infecting different fish species in Asia. Homology of the ompW protein suggested that strains with broad protective coverage could be identified as vaccine candidates. This study underscores the importance of combining genotyping with phenotyping for valid species classification. In addition, it accentuates the importance of phylogenetic comparison of bacterial antigens for identification of potential vaccine candidates.