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1.
A型产气荚膜梭菌最佳产毒时间的确定 总被引：1，自引：0，他引：1
测定了A型产气荚膜梭菌在庖肉培养基的生长曲线、培养液的pH值变化曲线以及不同培养时间提取的毒素液的蛋白质含量、溶血活性及卵磷脂酶活性。结果表明，A型产气荚膜梭菌在庖肉培养基培养8h是其a-毒素的最佳产毒时间。 相似文献
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多重聚合酶链反应检测环境中产气荚膜杆菌 总被引：12，自引：0，他引：12
产气荚膜杆菌根据产生4种主要毒素（α－β、ε、τ－毒素）可分为5种类型A－E型。在该研究中依据产气荚膜杆菌的5种毒素基因的序列，设计了5对PCR引物，建立了多重PCR方法，该方法可以快速区分5种类型的产气荚膜杆菌。并对68份环境样品（生活污水、生物肥料）进行检测和基因分型，共检出55株产气荚膜杆菌，其中A型产气荚膜杆菌50株，占总数的90％以上，B型、C型、D型只占5％，未检出E型产气荚膜杆菌，所有的分离株没有发现带有肠毒素。结果表明，目前环境中主要存在的菌型为A型菌，其他菌型的产气荚膜杆菌很少，而多数是非致病性产气荚膜杆菌。 相似文献
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犀牛产气荚膜梭菌的分离鉴定 总被引：1，自引：1，他引：0
从突然死亡的犀牛肠管中，分离到一株套氧菌，经鉴定为致病性Ａ型产气荚膜梭菌。该菌为革兰氏阳性大杆菌，在血平皿套氧培养，产生双环溶血的菌落，用产毒培养基培养，其上清液静脉注射０．２ｍｌ可致死小白鼠。证明该菌是造成犀牛死亡的病原。血清中和试验结果中Ａ型产气荚膜梭菌，该分离物鉴定为致病性的Ａ型产气荚膜梭菌。 相似文献
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经过对A型产气荚膜梭菌合成培养基pH值、灭菌方式和配制用水进行优化,确定最适pH值为8.0～8.5,灭菌方式为116℃30min,配制用水为去离子水。合成培养基培养产气荚膜梭菌CVCC37株6小时后毒力达50～100MLD/ml,随着时间的延长,毒力不再增强;培养温度为36℃或37℃时,产毒效果最佳。比较不同截留分子量的超滤膜浓缩效果,10Ku截留分子量的收获率为40%,其透出液静脉接种0.2ml,小鼠2/2死亡;而8Ku收获率达75%,其透出液静脉接种0.2ml,小鼠0/2死亡。因此,8Ku截留分子量膜包适宜对A型菌培养毒素的浓缩。 相似文献
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测定了产气荚膜梭菌B型、D型和腐败梭菌在新研制的厌氧菌基础培养基中的生长曲线和产毒能力等特性。结果表明,这些细菌可以在新培养基中良好生长和产毒。产气荚膜梭菌B 型经2 h 的适应期后,很快进入对数生长期,培养到8 h细菌密度接近最高值,OD630为4.329;经检测,培养4 h~24 h的细菌所产生的毒素(培养物上清)1μL~2μL可致死KM小鼠。产气荚膜梭菌D型的生长速度也较快,无适应期就直接进入对数生长期,培养到12 h 时细菌密度最高, OD630 为1.75;细菌最佳产毒期在6 h~14 h,培养物上清0.5μL~0.65μL可致死KM小鼠。腐败梭菌生长速度较慢,经6 h的适应期后,才进入对数生长期,培养到14 h时细菌密度最高,OD630为1.335;细菌毒力在培养后的6 h~24 h内10μL菌液可达到在24 h内致死KM小鼠的效果。 相似文献
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确定C型产气英膜梭菌合成培养基使用参数及建立配套的毒素浓缩工艺。比较不同pH值、灭菌温度、配制用水的合成培养基及其不同培养时间和温度下培养产气荚膜梭菌CVCC60102株的毒力;按毒素的分子量及超滤膜的截留分子量设计并比较2种不同浓缩工艺的毒素收获率及透出液的毒力。结果表明,pH值为8．0～8．4、灭菌方式为116℃30min、配制用水为去离子水时产毒最佳,毒力达到500—1000MLD／mL;合成培养基培养产气英膜梭菌CVCC60102株18h后毒力达500—1000MLD／mL,随着时间的延长,毒力不再增强;培养温度为36℃或37℃时,产毒效果最佳;不同截留分子量的超滤膜浓缩,10ku截留分子量的收获率为68％,其透出液静脉接种0．2mL,小鼠2／2死亡;而8ku收获率达80％,其透出液静脉接种0．2mL,小鼠0／2死亡。因此8ku截留分子量膜包适宜对C型菌培养毒素的浓缩。上述结果为C型产气荚膜梭菌合成培养基的应用提供了数据支撑。 相似文献
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为研制更有效的预防家畜D型产气荚膜梭菌肠毒血症的疫苗,本研究采用D型产气荚膜梭菌标准菌株增菌培养,经自制产毒培养基高效产毒,制备成D型产气荚膜梭菌氢氧化铝类毒素疫苗和白油类毒素疫苗。通过不同剂量疫苗免疫绵羊的攻毒保护试验和免疫绵羊的抗体水平监测,评估疫苗的免疫保护效果。结果表明:D型产气荚膜梭菌类毒素疫苗安全性良好,氢氧化铝苗和白油苗对绵羊有效免疫剂量均为4 m L(外毒素对小鼠半数致死量为2-6.4/m L),绵羊接种一个有效免疫剂量后,氢氧化铝疫苗免疫保护周期为6周以上;白油疫苗免疫保护周期为21周以上。本研究结果表明两种疫苗均具有良好的应用前景。 相似文献
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Samples of bottom muds from lakes and waterways in the Auckland area were inoculated into bottles of cooked meat medium. After incubation, the media were tested for production of Clostridium botulinum toxin which was detected with samples from 11 of the 20 sites examined. Although toxins produced from all positive samples were neutralized by specific antisera of both type C and D toxins, it is likely that C. botulinum type Calpha is the only type present in the Auckland area. All samples from other urban areas of the North Island gave negative results. 相似文献
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Samples of bottom muds from lakes and waterways in the Auckland area were inoculated into bottles of cooked meat medium. After incubation, the media were tested for reduction of Clostridium botulinum toxin which was detected with samples from 11 of the 20 sites examined. Although toxins produced from all positive samples were neutralized by specific antisera to both type C and D toxins, it is likely that C. botulinum type Cα is the only type present in the Auckland area. All samples from other urban areas of the North Island gave negative results. 相似文献
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REASONS FOR PERFORMING STUDY: Clostridial colitis and endotoxaemia of intestinal origin are significant causes of morbidity and mortality in horses. Intestinal adsorbents are available for treatment of these conditions; however, little information exists supporting their use. OBJECTIVES: To evaluate the ability of di-tri-octahedral smectite to bind to Clostridium difficile toxins A and B, C. perfringens enterotoxin and endotoxin, inhibit clostridial growth and the actions of metronidazole in vitro. METHODS: Clostridium difficile toxins, C. perfringens enterotoxin and endotoxin were mixed with serial dilutions of di-tri-octahedral smectite, then tested for the presence of clostridial toxins or endotoxin using commercial tests. Serial dilutions of smectite were tested for the ability to inhibit growth of C. perfringens in culture broth, and to interfere with the effect of metronidazole on growth of C. perfringens in culture broth. RESULTS: Clostridium difficile toxins A and B, and C. perfringens enterotoxin were completely bound at dilutions of 1:2 to 1:16. Partial binding of C. difficile toxins occurred at dilutions up to 1:256 while partial binding of C. perfringens enterotoxin occurred up to a dilution of 1:128. Greater than 99% binding of endotoxin occurred with dilutions 1:2 to 1:32. No inhibition of growth of C. difficile or C. perfringens was present at any dilution, and there was no effect on the action of metronidazole. CONCLUSIONS: Di-tri-octahedral smectite possesses the ability to bind C. difficile toxins A and B, C. perfringens enterotoxin and endotoxin in vivo while having no effect on bacterial growth or the action of metronidazole. POTENTIAL RELEVANCE: In vivo studies are required to determine whether di-tri-octahedral smectite might be a useful adjunctive treatment of clostridial colitis and endotoxaemia in horses. 相似文献
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Garcia JP Beingesser J Fisher DJ Sayeed S McClane BA Posthaus H Uzal FA 《Veterinary microbiology》2012,157(3-4):412-419
Clostridium perfringens type C is an important cause of enteritis and/or enterocolitis in several animal species, including pigs, sheep, goats, horses and humans. The disease is a classic enterotoxemia and the enteric lesions and associated systemic effects are thought to be caused primarily by beta toxin (CPB), one of two typing toxins produced by C. perfringens type C. This has been demonstrated recently by fulfilling molecular Koch's postulates in rabbits and mice. We present here an experimental study to fulfill these postulates in goats, a natural host of C. perfringens type C disease. Nine healthy male or female Anglo Nubian goat kids were inoculated with the virulent C. perfringens type C wild-type strain CN3685, an isogenic CPB null mutant or a strain where the cpb null mutation had been reversed. Three goats inoculated with the wild-type strain presented abdominal pain, hemorrhagic diarrhea, necrotizing enterocolitis, pulmonary edema, hydropericardium and death within 24h of inoculation. Two goats inoculated with the CPB null mutant and two goats inoculated with sterile culture media (negative controls) remained clinically healthy during 24h after inoculation and no gross or histological abnormalities were observed in the tissues of any of them. Reversal of the null mutation to partially restore CPB production also increased virulence; 2 goats inoculated with this reversed mutant presented clinical and pathological changes similar to those observed in goats inoculated with the wild-type strain, except that spontaneous death was not observed. These results indicate that CPB is required for C. perfringens type C to induce disease in goats, supporting a key role for this toxin in natural C. perfringens type C disease pathogenesis. 相似文献
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Chai T Wang L Wang H Duan H Müller W Zucker BA 《DTW. Deutsche tier?rztliche Wochenschrift》2007,114(10):394-396
In a pilot study the presence and frequency of Clostridium (C.) perfringens was investigated among apparently healthy farm animals in the Shandong province of China. 748 faecal samples were collected from 9 pig-, 4 sheep-, 7 cattle- and 5 rabbit farms. C. perfringens was isolated from 124 samples (16.6%). The isolates were classified into major toxin types by using PCR analysis detecting the genes encoding these toxins. All isolates were identified as C perfringens toxin type A. There are also some reports from different regions in China linking C. perfringens toxin type A strains to gastrointestinal diseases. Therefore further investigations about the epidemiologic role of C perfringens toxin type A strains in the Shandong region are necessary. Currently, cases of enterotoxemia from this region are investigated for the presence of C perfringens. 相似文献
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The effect of sulphite-reduction in 33 sample bacterial strains was tested. With regard to the capacity of reducing sulphite in modified sulphite-reduction media in a wide scale of bacterial strains the possibility of an application of selective media with an addition of various concentrations of antibiotic solutions was checked. A concentration of 750 microgram of D-cycloserine per 1 ml of the sulphite-reduction medium appeared to be the most advantageous for the isolation and detection of sulphite-reductive clostridia, above all of Clostridium perfringens. This concentration ensured also a sufficient inhibition of undesirable bacteria without any affection of the growth and capacity of Clostridium perfringens to reduce sulphite in the applied medium. 相似文献
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Two double sandwich enzyme-linked immunosorbent assays (ELISA) for Clostridium perfringens beta and epsilon toxins were assessed for routine diagnosis of enterotoxemias on intestinal contents of 151 sheep that died suddenly. Conventional tests (mouse assay and culture of organism) showed that 21 specimens were positive for Clostridium perfringens type C (beta toxin) and 39 were positive for Clostridium perfringens type D (epsilon toxin) enterotoxemias. Comparison of the ELISA results with conventional assays gave sensitivity and specificity rates respectively of 90.5% and 89.2% for beta toxin assay and 97.4% and 94.6% for epsilon toxin assay. With further refinement to improve the performance of the assay for beta toxin these tests could serve as a substitute for conventional tests in the laboratory diagnosis of Clostridium perfringens types B, C and D enterotoxemias. 相似文献
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van Asten AJ Allaart JG Meeles AD Gloudemans PW Houwers DJ Gröne A 《Veterinary microbiology》2008,127(3-4):412-416
Clostridium perfringens which is a causative agent of several diseases in animals and humans is capable of producing a variety of toxins. Isolates are typed into five types on the basis of the presence of one or more of the four major toxins genes, i.e. cpa, cpb, etx, and iap. A decade ago another toxin termed beta2 (beta2) and its gene (cpb2) were identified. Two alleles of cpb2 are known and a possible link between differences in gene expression and allelic variation has been reported. A correlation between the level of expression and the origin of the isolates has also been suggested. The demonstration and typing of the cpb2 gene in the genome of isolates can be seen as a vital part of research on the role of the beta2 toxin in the pathogenesis of disease. This study describes a PCR with a single primer set which in contrast to published primer sets recognizes both alleles. Subsequent restriction enzyme analysis of the PCR product enables typing of the alleles. Applying this protocol on a total of 102 isolates, a sub-variant was found which occurred only in C. perfringens isolates from pigs and appeared to be the predominant variant found in C. perfringens isolates from this species. 相似文献