胸膜肺炎放线杆菌对仔猪的感染试验

用作者分离鉴定的胸膜肺炎放线杆菌感染仔猪,临床特征为:呼吸困难,食欲不振,体温升高;病理解剖学变化为:胸腔有大量的积液,心包增厚,并且在肺脏和胸膜粘连胸膜增厚,肺脏萎缩,病灶区呈暗红色,轮廓清晰;病理组织学变化为:肺脏、肝脏和肾脏脉血管均有扩张出血,组织发生坏死.     

胸膜肺炎放线杆菌ApxIA在大肠杆菌中的可溶性表达及纯化

以胸膜肺炎放线杆菌1型参考菌株App-259株基因组DNA为模板,PCR扩增apxIA全基因,构建表达重组质粒apxIA-c2X,并将其转化至大肠杆菌TB1,SDS-PAGE和Western-blot分析表达产物.结果表明:成功构建了apxIA-C2x表达质粒,重组菌在15℃经0.2mmol/L IPTG诱导16 h获...     

纤维素结合域的酿酒酵母表面展示及其黏附位点初探

利用酿酒酵母表面展示系统表达产琥珀酸丝状杆菌S85纤维素结合域家族2(CBD2),分析其纤维黏附位点.将CBD2基因插入质粒pYDI的AGOg2 3'端,构建pMCBD2重组质粒,化学转化pMCBD2至酿酒酵母EBY100中,2%半乳糖诱导CBD2表达于酿酒酵母表面.利用免疫组化技术检测重组酵母细胞在稻草茎细胞壁上的黏...     

猪传染性胸膜肺炎放线杆菌的分离鉴定及药敏试验

为了给天津某规模猪场提供猪传染性胸膜肺炎(PCP)的科学防控和合理的用药方案,本试验对该猪场疑似患PCP的病猪进行临床综合诊断和病理组织学观察,无菌采集病料,通过细菌的分离与培养、镜检、生化试验、卫星试验、PCR检测、动物致病性试验及药敏试验等实验室方法对分离菌进行系统分析。结果发现,病猪呼吸困难,病理剖检和病理组织学观察可见有典型的纤维素性肺炎变化;显微镜下分离菌呈多形性的革兰氏阴性杆菌,且其生化试验、卫星试验结果与传染性胸膜肺炎放线杆菌(APP)特性一致;用APP APX ⅣA毒素基因特异性引物扩增结果为阳性;该APP分离菌对小鼠具有致病性,且对头孢噻肟、氟苯尼考等药物高度敏感。根据实验室检测结果并结合临床综合诊断,最终判定该细菌分离株为猪传染性APP。     

检测猪胸膜肺炎放线杆菌ApxⅣ抗体乳胶凝集试验方法的建立

采用Ni-NTA His.Bind方法纯化pET-28a-ApxⅣ2表达蛋白,以羧化乳胶为载体,经化学交联法致敏乳胶,对致敏条件优化后进行质量检测。结果显示,在pH 4.7的PBS缓冲液中,乳胶浓度为2%、蛋白质量浓度为1.5g/L,偶联8h后制备的致敏乳胶凝集反应最好,致敏乳胶抗原无自凝现象;与副猪嗜血杆菌、猪瘟病毒、猪伪狂犬病病毒、猪繁殖与呼吸综合征病毒、大肠杆菌和多杀性巴氏杆菌阳性血清不发生凝集;批内重复、批间重复试验很稳定;阳性血清敏感性可达1∶32。对比试验中与ELISA方法的符合率为80%,2种方法检测的结果基本相符。结果表明,试验初步建立了检测猪胸膜肺炎放线杆菌ApxⅣ毒素抗体的乳胶凝集方法,为猪传染性胸膜肺炎的快速诊断提供了技术支撑。     

胸膜肺炎放线杆菌毒力因子研究进展

胸膜肺炎放线杆菌是引起猪传染性胸膜肺炎的重要病原。在APP致病过程中各种毒力因子发挥着决定性的作用,且致病机理较为复杂。目前,疫苗免疫是预防和控制该病的有效措施。研制亚单位疫苗及基因工程苗具有良好的应用价值,而了解和认识APP的毒力因子的特性是开展这一工作的基础。     

一例猪传染性胸膜肺炎的诊治

猪传染性胸膜肺炎是严重危害现代养猪业的一种呼吸道传染病,广泛流行于全国各地。在内蒙古包头市一养猪场分离培养出1株猪传染性胸膜肺炎放线杆菌,并通过治疗试验发现氟苯尼考和强力霉素对该菌株治疗效果好。对猪传染性胸膜肺炎的病因进行了分析,并提出了控制疫情的有效措施。     

Specific immune response of mares and their newborn foals to Actinobacillus spp. present in the oral cavity

Oral swab samples, serum and colostrum was taken from 15 mares and 14 of their foals, within 24 h of birth. The presence of antibody against Actinobacillus spp. isolated from the oral cavity was investigated using agar gel immunodiffusion. Antibodies against 48 out of the 77 Actinobacillus isolates from all horses in the study were present in the respective sera of 13 mares and 9 foals. In 11 mother-foal pairs, the antibody content of the foal serum was similar to that of the mare, and in 9 cases this was reflected in the antibody content of colostrum from the mare. The results indicate that an immune response to Actinobacillus spp. colonising the oral cavity is present in many adult horses and that this immune response can be transferred from mother to foal via colostrum.     

Putative biomarkers for evaluating antibiotic treatment: an experimental model of porcine Actinobacillus pleuropneumoniae infection

Biomarkers of infection were screened for their possible role as evaluators of antibiotic treatment in an aerosol infection model of porcine pneumonia caused by Actinobacillus pleuropneumoniae (Ap). Following infection of 12 pigs, clinical signs of pneumonia developed within 20 h, whereafter the animals received a single dose of either danofloxacin (2.5mg/kg) or tiamulin (10 mg/kg). To test the discriminative properties of the biomarkers, the dosage regimens were designed with an expected difference in therapeutic efficacy in favour of danofloxacin. Accordingly, the danofloxacin-treated pigs recovered clinically within 24h after treatment, whereas tiamulin-treated animals remained clinically ill until the end of the study, 48 h after treatment. A similar picture was seen for the biomarkers of infection. During the infection period, plasma C-reactive protein (CRP), interleukin-6 and haptoglobin increased, whereas plasma zinc, ascorbic acid and alpha-tocopherol decreased. In the danofloxacin-treated animals, CRP, interleukin-6, zinc, ascorbic acid and alpha-tocopherol reverted significantly towards normalisation within 24h of treatment. In contrast, signs of normalisation were absent (CRP, zinc and ascorbic acid) or less marked (interleukin-6 and alpha-tocopherol) in the tiamulin-treated animals. Plasma haptoglobin remained elevated throughout the study in both groups. This indicates that CRP, zinc, ascorbic acid and to a lesser extent interleukin-6 and alpha-tocopherol might be used to evaluate antibiotic treatment of acute Ap-infection in pigs. The present model provides a valuable tool in the evaluation of antibiotic treatments, offering the advantage of clinical and pathological examinations combined with the use of biochemical infection markers.