Botulinum toxin: Bioweapon & magic drug.

Botulinum neurotoxins, causative agents of botulism in humans, are produced by Clostridium botulinum, an anaerobic spore-former Gram positive bacillus. Botulinum neurotoxin poses a major bioweapon threat because of its extreme potency and lethality; its ease of production, transport, and misuse; and the need for prolonged intensive care among affected persons. A single gram of crystalline toxin, evenly dispersed and inhaled, can kill more than one million people. The basis of the phenomenal potency of botulinum toxin is enzymatic; the toxin is a zinc proteinase that cleaves neuronal vesicle associated proteins responsible for acetylcholine release into the neuromuscular junction. As a military or terrorist weapon, botulinum toxin could be disseminated via aerosol or by contamination of water or food supplies, causing widespread casualties. A fascinating aspect of botulinum toxin research in recent years has been development of the most potent toxin into a molecule of significant therapeutic utility. It is the first biological toxin which is licensed for treatment of human diseases. In the late 1980s, Canada approved use of the toxin to treat strabismus, in 2001 in the removal of facial wrinkles and in 2002, the FDA in the United States followed suit. The present review focuses on both warfare potential and medical uses of botulinum neurotoxin.

Neonatal immune response of Brazilian beef cattle to vaccination with clostridium botulinum toxoids types C and D by indirect ELISA

Types C and D strains of Clostridium botulinum are commonly related to avian and mammalian botulism. Although there are numerous vaccine recommendations, little research has been conducted to indicate the real effectiveness of vaccine timing or the ideal immunization protocol for young beef calves. Four commercially available vaccines, two bivalent (Clostridium botulinum types C and D; vaccines 1 and 2) and two polyvalent (all Clostridium spp. including Clostridium botulinum types C and D; vaccines 3 and 4), that are currently used in Brazilian herds, were tested in order to verify the maternal immune response. One hundred cows, divided into four vaccinated groups and one unvaccinated group, were given a two-dose subcutaneous immunization, at day zero, followed by a second dose given at 42 days post-vaccination, which corresponded to 40 days before birth. Serum samples (n = 75) were collected only from healthy neonatal calves at 0, 7, 45 and 90 days post-calving (DPC) and subjected to indirect ELISA using the purified C and D holotoxins as capture antigens. The serological profile showed that all vaccines were able to induce a satisfactory neonatal immune response to both holotoxins at 7 DPC. However, at 45 and 90 DPC, a significant reduction (p < 0.05) was observed in the antibody level against C and D holotoxins in all tested vaccines. Neonatal immunization in calves is compromised by significant levels of maternal antibodies so that the necessity of planning a calf vaccination program involves assessment of disease risks at the production site. Finally, our findings represent the first demonstration of maternal immunity transferred to neonatal beef calves, including immunity levels after vaccination against Clostridium botulinum toxoids C and D.

Efecto inhibitorio de clostridium perfringens sobre C. botulinum en muestras de suelo / Inhibitory effect of Clostridium perfringens on C. botulinum in soil samples

Introducción. La frecuencia de aislamiento de Clostridium botulinum en Costa Rica y en otros sitios es baja, en tanto que C. perfringens es la especie toxigénia más abundante en la naturaleza. Se ha descrito que C. perfringens podría impedir el aislamiento de C. botulinum o la producción de su toxina a partir de muestras de suelo, razón por la cual se pensó en investigar el efecto al respecto, de cepas de C. perfringens aisladas de suelos costarricenses. Material y Métodos. Se analizaron 38 cepas de C. perfringens obtenidas de suelos costarricenses para demostra si los sobrenadantes de cultivo inhibían el crecimiento de C. botulinum A (ATCC 19399). Además, se realizaron cultivos mixtos de C. botulinum y C. perfringens para evaluar si se impedía el crecimiento y la producción de toxina botulínica. Resultados. El 58 por ciento de las cepas de C. perfringens tuvo efecto inhibitorio sobre el crecimiento de C. botulinum; al menos dos cepas inhibían totalmente el efecto de la toxina botulínica en los cultivos mixtos aún cuando se demostró la presencia de células viables de C. botulinum. El número mínimo de células de C. perfringens necesarias para lograr lo anterior fue de 10 a la octava células. Conclusión. Es posible que la presencia de C. perfringens limite el aislamiento o demostración de C. botulinum en suelos costarricenses. Se requiere investigar si las cepas nativas de C. perfringens tienen efecto sobre otras cepas y otros grupos de C. botulinum