D型产气荚膜梭菌ε毒素研究进展

D型产气荚膜梭菌常引起新生羔羊痢疾和山羊、牛等家畜的肠毒血症,致死性强,对畜牧业造成很大的危害.ε毒素是D型产气荚膜梭菌的主要致死性毒力因子和保护性抗原,从分子生物学的角度对该毒素的研究具有重要实际意义.论文主要对国内外关于D型产气荚膜梭菌ε毒素分子生物学结构与性质,ε毒素引起的家畜肠毒血症以及对其作用靶器官肾脏和脑组织破坏的致病机理进行了介绍,对国内外D型产气荚膜梭菌ε毒素预防措施进行了综述,为研究D型产气荚膜梭菌ε毒素结构与功能的关系以及预防治疗动物肠毒血症提供参考.     

G型产气荚膜梭菌NetB毒素研究进展

G型产气荚膜梭菌可引起鸡坏死性肠炎和肠毒血症,致病力强,在自然界中广泛存在,严重危害养鸡业的发展。坏死性肠炎B样毒素(necrotic enteritis B-like toxin, NetB)是近年来发现的是一种新的β-成孔毒素(β-pore-forming toxin,β-PFT),是G型产气荚膜梭菌的主要致病性毒素和保护性抗原,深入研究该毒素的结构功能及致病机理对于鸡坏死性肠炎的防控具有重要意义,但至今尚无相关系统性综述报道。鉴于此,论文主要对国内外关于G型产气荚膜梭菌的流行概况、NetB毒素的分子结构特征、生物学特性、致病机理及其相关防治制剂等方面的研究进行综述,为进一步基于NetB毒素研制鸡坏死性肠炎的防治制剂提供参考。     

产气荚膜梭菌主要外毒素最新研究进展

产气荚膜梭菌是一种重要的人兽共患病的病原体,可引起人的食物中毒和抗生素相关腹泻.近年来,对产气荚膜梭菌的主要外毒素研究取得了重大进展.本文综述了产气荚膜梭菌主要外毒素的组成、结构、理化性质、作用机理、检测及分子遗传学等方面的研究进展.     

产气荚膜梭菌肠毒素的致病机理研究进展

产气荚膜梭菌是一种重要的人兽共患病的病原体，可引起人的食物中毒和抗生素相关腹泻，产气荚膜梭菌肠毒素是该菌的一个非常重要的致病毒素，在引起人的胃肠疾病方面起着关键性的作用，本文对产气荚膜梭菌肠毒素产生、细胞毒性和组织学作用以及在胃肠粘膜上造成损伤的致病分子机理等方面的研究内容进行论述。     

产气荚膜梭菌α毒素研究进展

α毒素是产气荚膜梭菌的主要毒素和致病因子之一。本文综述了产气荚膜梭菌α毒素的检测，基因的克隆，表达和调控以及毒素的结构与功能等方面的研究进展。     

产气荚膜梭菌的主要毒素及其在肉鸡坏死性肠炎致病机理中的作用研究进展

肉鸡坏死性肠炎(necrotic enteritis,NE)是产气荚膜梭菌(Clostridium perfringens)引发的一种严重的肠道疾病,给肉鸡业造成了巨大的经济损失。为深入了解肉鸡坏死性肠炎的致病因子和致病机理,本文对产气荚膜梭菌的主要毒素及其在肉鸡坏死性肠炎致病机理中的作用进行了概述,为该病的临床诊断、监测和防控提供参考。     

减抗禁抗背景下鸡产气荚膜梭菌的防治

为更好地防治鸡的产气荚膜梭菌病，减少该病对养殖行业造成的损失，本文结合当前减抗禁抗的新形势，从生物安全防控、检测技术研究、科学免疫接种、合理规范使用抗菌药等方面对鸡产气荚膜梭菌病的防治进行了探讨，为养殖场有效防治鸡产气荚膜梭菌病提供了新思路。     

浅析牛产气荚膜梭菌病

<正>近年来产气荚膜梭菌对中国养牛业的危害巨大,其流行型别和致病特点较以往也在发生变化,本文主要对牛产气荚膜梭菌病在流行病学、临床症状、诊断方法以及防制措施方面进行了综述。产气荚膜梭菌原称魏氏梭菌,是一种重要的人兽共患病原菌,广泛分布于自然界,也是人和动物肠道中的常在菌之一,能产生多种外毒素,对人和动物致病,是引起各种动物坏死性肠炎、肠毒血症,人类食物中毒和创伤性气性坏疽的主要病原菌之一。产气荚膜梭菌病主     

产气荚膜梭菌α毒素免疫组化检测方法的建立

为建立检测产气荚膜梭菌α毒素的方法,本研究以抗产气荚膜梭菌α毒素单克隆抗体为特异性检测抗体,对人工腹腔注射α毒素的病死兔器官组织进行免疫组化染色,经反应条件优化,建立了产气荚膜梭菌α毒素的免疫组化检测方法。应用该方法对临床16例疑似产气荚膜梭菌病兔组织中的α毒素进行检测,同时进行病原菌分离鉴定。结果显示,该方法可以检测到人工感染兔心脏、肺脏、脾脏、肾脏、膀胱、肝脏、胃、小肠、盲肠和延脑中的α毒素分布,对照组则均为阴性,具有良好的特异性;临床应用检测结果表明:16例疑似病兔胃和肾脏中α毒素的检测均为阳性,检测阳性率高于细菌分离培养。本研究建立的该方法可以用于产气荚膜梭菌病的临床诊断,也为该毒素在动物机体内的分布规律及致病机理的研究提供了可靠的手段。     

产气荚膜梭菌ε毒素研究进展

产气荚膜梭菌是一种重要的人畜共患细菌性传染病病原,在自然界中分布极广,一定条件下可引起多种疾病。该菌常通过其外毒素危害人和动物机体,所产毒素主要有α、β、ε和ι4种外毒素。根据毒素产生的情况,将产气荚膜梭菌分为A、B、C、D、E、F和G 7个型。ε毒素毒力最强,主要由B型和D型菌分泌。论文通过致病机理、病理变化、流行特点及相关疫苗研究方面对产气荚膜梭菌ε毒素研究进展进行综述,以期为产气荚膜梭菌病的防控提供参考。     

Clostridial enteric infections in pigs.

Clostridium perfringens types A and C and Clostridium difficile are the principal enteric clostridial pathogens of swine. History, clinical signs of disease, and gross and microscopic findings form the basis for a presumptive diagnosis of C. perfringens type-C enteritis. Confirmation is based on isolation of large numbers of type-C C. perfringens and/or detection of beta toxin in intestinal contents. Diagnosis of C. perfringens type-A infection, however, remains controversial, mostly because the condition has not been well defined and because type-A organisms and their most important major (alpha) toxin can be found in intestinal contents of healthy and diseased pigs. Isolation of large numbers of C. perfringens type A from intestinal contents, in the absence of other enteric pathogens, is the most reliable criterion on which to base a diagnosis. Recently, beta2 (CPB2) toxin-producing C. perfringens type A has been linked to disease in piglets and other animals. However, implication of CPB2 in pathogenesis of porcine infections is based principally on isolation of C. perfringens carrying cpb2, the gene encoding CPB2, and the specific role of CPB2 in enteric disease of pigs remains to be fully defined. Clostridium difficile can also be a normal inhabitant of the intestine of healthy pigs, and diagnosis of enteric infection with this microorganism is based on detection of its toxins in feces or intestinal contents.     

几种中草药提取物对感染产气梭菌肉鸡生长性、血液生化指标及肠道组织学的影响

本试验将560只Ross 308肉鸡随机分为7组,每组8个重复,每个重复10只鸡。各组日粮处理如下:对照组饲喂基础日粮,未感染产气梭菌,T1组感染产气梭菌,T2组感染产气梭菌+0.2 g/kg阿维霉素,T3组感染产气梭菌+0.40 g/kg百里香酚,T4组感染产气梭菌+0.2 g/kg血根碱,T5组感染产气梭菌+0.5 g/kg香芹酚、肉桂醛和辣椒素混合物,T6组感染产气梭菌+0.2 g/kg百里香酚和茴香混合物。结果显示:T2组第3周料重比显著高于对照组(P<0.05)。T1组屠宰率显著下降(P<0.05),小肠重量显著增加(P<0.05)。第4周时,T6组血液总蛋白和球蛋白含量显著升高(P<0.05),T5组肝脏谷丙转氨酶活力显著升高(P<0.05)。T5和T6组硫代巴比妥酸反应物含量均显著升高(P<0.05)。同样,T5和T6组绒毛高度和隐窝深度也显著增加(P<0.05)。综上所述,与抗生素相比,肉鸡日粮添加中草药制剂在维持产气荚膜梭菌感染肉鸡生长性能和血液生化特性方面具有应用的优势。     

Studies of necrotizing enteritis of suckling piglets (Clostridium perfringens type C enterotoxemia) in industrialized sow breeding units. 4. Epizootiology]

Necrotising enteritis had been the cause of death of 4.9 per cent in 5,177 nursed piglets, which was established by pathological examination. The number of piglets, in that context, which had come from industrialised sow breeding units was equivalent to 92 per cent. The nursed piglet held the third position, next to smaller ruminants (19.4 per cent) and fowl (6.0 per cent), with regard to the occurrence of Clostridium perfringens enterotoxemia or necrotising enteritis in 112,218 animals which were pathologically examined after death. Necrotising enteritis so far has been rare in the GDR. No regional accumulation has been observed. Several outbreaks on industrialised sow breeding units actually remained stationary. The occurrence of the disease may be favoured by a number of factors which are conducive to accumulation of Clostridium perfringens Type C in a given stock. Group keeping of pregnant sows, simultaneous farrowing of larger groups of sows, group treatment of nursed piglets, using neomycin, chloramphenicol, oxytetracycline, and other antibiotics to which Clostridium perfringens is primarily resistant or has acquired resistance in the course of time are some of those contributive factors. Transmission of Clostridium perfringens Type C through feedstuff is possible, though it would lead to a real outbreak only by high intensity of the contamination, and it played a minor role in proliferation of the disease. 3479 Clostridium perfringens strains were isolated from 9,481 animals, both clinically intact and after death, with 30 species being included. Type classification revealed 2454 strains of Type A (70 per cent), 204 of Type D (5.88 per cent), 164 of Type C (four per cent), and 48 of Type B (1.34 per cent). There were 688 atoxic strains (17 per cent). Swine is the major carrier of Clostridium perfringens Type C, with 87 per cent of all Clostridium perfringens Type C strains having been isolated from swine. Swine was followed by fowl (four per cent), sheep (four per cent), cattle, rabbit, and dog (1.27 per cent each). Clostridium perfringens Type C was obtained from the faeces of clinically intact sows in seven instances, including two cases with sows (0.46 per cent) from farms with no previous record of necrotising enteritis.     

Population-based study of fecal shedding of Clostridium perfringens in broodmares and foals

OBJECTIVE: To determine the percentage of broodmares and foals that shed Clostridium perfringens in their feces and classify the genotypes of those isolates. DESIGN: Prospective cross-sectional study. ANIMALS: 128 broodmares and their foals on 6 equine premises. PROCEDURES: Anaerobic and aerobic bacteriologic cultures were performed on feces collected 3 times from broodmares and foals. All isolates of C. perfringens were genotyped. RESULTS: Clostridium perfringens was isolated from the feces of 90% of 3-day-old foals and 64% of foals at 8 to 12 hours of age. A lower percentage of broodmares and 1- to 2-month-old foals shed C. perfringens in their feces, compared with neonatal foals. Among samples with positive results, C. perfringens type A was the most common genotype identified (85%); C. perfringens type A with the beta2 toxin gene was identified in 12% of samples, C. perfringens type A with the enterotoxin gene was identified in 2.1% of samples, and C. perfringens type C was identified in < 1% of samples. CONCLUSIONS AND CLINICAL RELEVANCE: Clostridium perfringens was identified from the feces of all but 6 foals by 3 days of age and is likely part of the normal microflora of neonatal foals. Most isolates from broodmares and foals are C. perfringens type A; thus, the clinical relevance of culture results alone is questionable. Clostridium perfringens type C, which has been associated with neonatal enterocolitis, is rarely found in the feces of horses.     

几种培养基对A型产气荚膜杆菌产毒效果的比较

本文以四种培养基，对同一A型产气荚膜杆菌分离株G3的生长曲线和培养液pH值变化进行了测定，并比较了四种培养基的产毒效果。结果表明：A型产气荚膜杆菌在四种培养基上的生长内线基本一致，但pH值变化有差异，其中以疱肉培养液的pH值变化幅度最小，且其毒素产量最多，活性最高。由此可见，疱肉培养基可作为A型产气荚膜杆菌的产毒培养基。     

产气荚膜梭菌肠毒素的分子生物学研究进展

产气英膜梭菌(Clostridium perfringens)是一种重要的人兽共患病的病原体,它是一类革兰氏阳性产芽孢的厌氧梭菌,可引起人的食物中毒和肠毒素相关腹泻.近年来,研究人员发现由产气英膜梭菌导致腹泻的主要原因与该菌在芽孢形成过程中产生的一种肠毒素有关.文章重点针对产气英膜梭菌肠毒素的生物学特性和致病机制等方面的研究做一综述.     

Proteases of Clostridium botulinum. V. Studies on the serological relationship between proteases from Clostridium botulinum and other spore-forming bacteria

By the use of the electrophoretic casein precipitating inhibition test (CPI-test) the serological relationship between proteolytic enzymes produced by different species within the genera Clostridium and Bacillus has been tested. The proteases produced by Clostridium botulinum types A, B, C, D and F cross-reacted with each other. Clostridium botulinum strain 84 was inhibited by antiproteases produced against Clostridium sporogenes, Clostridium botulinum types C and F (protease F I and F II), but not by antiproteases against Clostridium botulinum types B and F (protease II), Clostridium bifermentans and Clostridium perfringens. The protease of the newly described Clostridium botulinum strain 89 (type G) was inhibited by Clostridium sporogenes antiprotease, but not by any of the other antiproteases. It is not possible to differentiate between Clostridium botulinum, Clostridium sporogenes and Clostridium perfringens by use of serological differentiation of their proteolytic enzymes. The protease of Clostridium bifermentans is not serologically related to any of the species tested in this investigation. Proteases produced by different Bacilli were not inhibited by antiproteases from Clostridium botulinum types B, C and F, Clostridium sporogenes, Clostridium bifermentans, and the two strains of Clostridium perfringens tested. This investigation indicates a serological relationship between proteases from different Clostridium species, but not a serological relationship between proteases produced by the Clostridium species and Bacillus species tested.     

产气荚膜梭茵肠毒素的分子生物学研究进展

产气荚膜梭茵（Clostridium perfringens）是一种重要的人兽共患病的病原体，它是一类革兰氏阳性产芽孢的厌氧梭茵，可引起人的食物中毒和肠毒素相关腹泻。近年来，研究人员发现由产气荚膜梭茵导致腹泻的主要原因与该茵在芽孢形成过程中产生的一种肠毒素有关。文章重点针对产气荚膜梭茵肠毒素的生物学特性和致病机制等方面的研究做一综述。