Clostridium botulinum in fish.

1407 fish caught in Scandinavian waters, the North Sea and the North Atlantic have been examined for the presence of Cl. botulinum. The incidence in gut samples expressed as percentage of fish tested was generally highest in fish from Scandinavian coastal waters and the Baltic Sea (4--43%), decreasing in fish from the North Sea (0--8%), and the organism was practically absent in fish from the North Atlantic. When gut samples were examined, the incidence was highest in demersal fish (cod and flatfish) as compared with pelagic fish (herring). The latter fish species were mainly contaminated on outer surfaces and gills. Only type E was detected in this survey, and Cl. botulinum was not detected in any wild fresh water fish. It is suggested that type E spores may originate in the sea bed and that they be spread by fish and water currents.     

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.     

Proteases of Clostridium botulinum. VI. The role of trypsin, Clostridium botulinum proteases and protease inhibitors in the formation and activation of toxin in growing cultures of Clostridium botulinum

In this study the influence of bovine serum protease inhibitors, trypsin and proteases produced by different types of Clostridium botulinum has been investigated. Trypsin and botulinum proteases had the capability of increasing the toxicity in growing cultures in Clostridium botulinum types A, B and E. Trypsin increased the toxin level to a greater extent than proteases from Clostridium botulinum types A, B, C and F. Protease inhibitors did not influence the toxin formation to any extent compared with the controls. The combined effects of proteases and protease inhibitors on the development of toxin in Clostridium botulinum type B were also investigated by adding proteases and protease inhibitors to the same culture at different time intervals. Protease inhibitors did not reduce the toxicity of the cultures as compared to the controls. Altogether a complex relationship seems to exist between protoxin, toxin, proteases and inhibitors in the culture, and the order and time sequence of addition seem to be of importance. The results obtained in this investigation indicate that proteases of Clostridium botulinum play a part in the formation and/or activation of toxin in growing cultures of proteolytic strains such as Clostridium botulinum types A and B. As to the activation of protoxin and progenitor toxin produced by non-proteolytic Clostridium botulinum types B and E, botulinum proteases showed a marked capability of increasing the toxicity in these cultures. Trypsinization may be valuable for the detection of Clostridium botulinum types A and B in foods, as well as for type E, where it is commonly used.     

The taxonomic position of Clostridium botulinum type c.

Experimental evidence is produced to justify abandoning the practice of subdividing Costridium botulinum Type C into type Calpha and Cbeta.     

肉毒梭菌毒素灭鼠研究进展

就肉毒梭菌毒素用于灭鼠的研究和应用情况进行了综述，充分肯定了C型肉毒梭菌毒素灭鼠制剂毒力强，适口性好，对非靶动物毒性低，作用缓慢，无2次中毒，易降解和适合于规模灭鼠的特点，为鼠害防治提供了新的思路。     

鸡肉毒梭菌中毒的诊治

我镇某散养鸡场，07年6月28目，2月龄2000只鸡群中突然发生运动神经麻痹和延脑麻痹为主要症状的疾病，同时发生大批死亡。前后共发病928只，发病率46．4％，死亡886只，病死率89．7％。通过发病情况调查，临诊症状观察，病理剖检及动物播种试验，初步诊断为肉毒梭菌毒系中毒症。     

Proteases of Clostridium botulinum. I. Classification of proteases and literature survey

Proteolytic activity has long been regarded as an important characteristic for distinguishing between different types of Clostridium botulinum. While all strains of Clostridium botulinum type A examined so far possess proteolytic activity, the types B and F have both proteolytic and non-proteolytic varieties. Clostridium botulinum types C, D and E were generally regarded as non-proteolytic, but different investigators have shown proteolytic activity in certain strains of these types. A summary of the classification of proteolytic enzymes in general is given and further, investigations are reviewed on the proteolytic activity in Clostridium botulinum.     

Avian botulism and the high prevalence of Clostridium botulinum in the Norflok Broads.

An account is given of a severe outbreak of type C botulism in waterfowl that occurred on the Norfolk Broads during the exceptionally warm summer of 1975. Forty-five mud samples were collected from 22 well distributed aquatic sites representing a considerable proportion of the total number of Broads. All samples except one (ie, 97-8 per cent) were shown to contain Clostridium botulinum and 58 per cent contained more than one type of the organism. Types B, C and E were demonstrated in 62-2 per cent, 51-1 per cent and 60 per cent of samples respectively. Recent surveys, made by identical methods, of aquatic environments in the London area and the Camargue (France) showed prevalences of Cl botulinum of 72-5 per cent and 4-5 per cent respectively. It seems likely that the Norfolk Broads will continue to present a risk to waterfowl from botulism in future hot summers.     

A Clostridium botulinum type B vaccine for prevention of shaker foal syndrome

A toxoid was prepared from type B toxin of Clostridium botulinum by treatment with 0.6% formalin for 6 weeks. The toxoid was adsorbed to aluminium hydroxide and this vaccine was evaluated for safety in guinea pigs, mice and horses, and for immunogenicity in guinea pigs and horses. Neutralising antitoxin was demonstrated in adult horses receiving two 2 ml subcutaneous doses 6 weeks apart, and in a foal which suckled its vaccinated dam. Another vaccinated mare and the passively immunised foal were protected against subcutaneous injection of 1600 and 2000 mouse lethal doses of toxin per kg respectively.     

Susceptibility of mink to Clostridium botulinum type E toxin

Experiments aiming at elucidation of the toxicity of Clostridium botulinum type E for mink are described. The observations indicate that amounts in the order of 2 x10^s intraperitoneal MLD (mice) or approximately 200 MLD per g of type E toxin will kill a mink after oral administration. The symptoms observed in the animals were atypical as there was an unusually short period between administration of the toxin and the onset of symptoms and deaths of the animals. Similar results were obtained when Clostridium botulinum type E toxin was fed to Swiss mice. When mice were protected by subcutaneous injections of type E antitoxin prior to feeding the animals survived without showing any symptoms.Subcutaneous injection of type E toxin in amounts of the order of 2 x10^s intraperitoneal MLD (mice) killed mink, and typical symptoms of botulism were observed. This quantity corresponds to ap-proximately 2 intraperitoneal MLD (mice) per g.Comparison is made with previous observations obtained in similar experiments made with Clostridium botulinum type C toxin. It is shown that mink arc substantially less susceptible to type E than to type C toxin when the toxins are given by mouth. On this basis previous results in reports on outbreaks of botulism in mink caused by Clostridium botulinum type E may be regarded as questionable.     

一起牛出败的诊断及体会

２０００年８月 ,我市郊区王某家两头牛突然先后死亡 ,以咳嗽、流泪、流涎、呼吸困难和咽喉部前颈部水肿为主要症状 ,并伴有多发性出血。由于该病病程短 ,死亡率高 ,临床症状与炭疽有相似之处 ,引起了我市畜牧部门和畜主重视。经过临床症状和实验室诊断 ,最后确诊为牛出败病。１发病情况及临床症状王某家共养４头牛 ,分两圈饲养 ,当天天气闷热 ,中午１２点左右 ,王某喂牛时发现一头牛已死亡 ,王某还以为是牛中暑致死 ,没引起重视 ,为了挽回损失 ,王某立刻对死牛放血剥皮。大约１２点半左右 ,同圈的另一头牛突然表现为肌肉震颤 ,体温升高 ,精…     

Susceptibility of mink to Clostridium botulinum type C toxin

Investigations to determine the exact susceptibility of mink to Clostridium botulinum type C toxin clearly showed that mink were considerably less resistant to this toxin than has previously been described. Mink weighing approximately 900 g were killed by 360 MLD when toxin was mixed into the feed. By subcutaneous injection, the lethal dose was determined to be in the range of 18 to 36 MLD.When comparing the susceptibility per g of body weight after parenteral application of the toxin, mink proved to be less resistant than mice to this type of toxin. Continued feeding tests in mink with suspected material is pointed out as a preferable method for practical demonstrations of Clostridium botulinum type C toxin in cases where the toxin content in the suspected material is very low (1 MLD per g or less).     

D型肉毒梭菌菌苗及诊断用血清的研究

利用在国内首次从动物体内分出的D型肉毒梭菌,研制了D型肉毒梭菌菌苗及诊断血清。结果表明:采用透析培养技术制备的D型肉毒梭菌磷酸铝苗,免疫性良好,对家兔和豚鼠的免疫保护力均为100%;制备的诊断血清每毫升可中和10000 MLD毒素,可用于肉毒梭菌菌型鉴定。