تسجيل الدخول

تسجيل

Bacteria , Clostridium spp

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  P116-117

2026-09-27

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Bacteria , Clostridium spp

Botulinum and tetanus neurotoxins are produced by strictly anaerobic bacteria belonging to the genus Clostridium and cause the neuroparalytic syndromes of botulism and tetanus. The botulinum toxins consist of at least four peptides with molecular sizes that range from 150 to 900 kDa. The tetanus toxin has two disulfide-linked peptide chains of molecular size 50 kDa and 100 kDa. The clostridial neurotoxins are the most potent toxins known, with a mouse-lethal dose of 0.3 ng/kg and a reported LD50 in unvaccinated humans of 2.5 ng/kg for tetanus toxin. Botulinum toxins are food poisons, whereas the tetanus toxin is not. Tetanus follows the contamination of necrotic wounds with spores of C. tetani. Tetanus is rare in countries with immunisation programmes, but it has a high case fatality rate of 24%. An estimated 800 000 newborns die from neonatal tetanus worldwide each year. Treatment with antitoxin and intravenous administration of penicillin soon after infection may reduce mortality. Classic food-borne botulism occurs after ingestion of food contaminated by preformed toxin of C. botulinum. The clinical presentations are stereotypical. Within 12–36 h of ingestion, the patient develops diplopia and ptosis, followed by a descending pattern of weakness that affects the upper and then the lower limbs, and respiratory paralysis in severe cases. There is no specific treatment for botulism; recovery is not uncommon but it requires the regeneration of new motor endplates, which takes weeks. Laboratory proof of botulism requires the detection of the toxin in the patient’s blood or stools. If still available, the suspected food should also be tested for the toxin. A number of immunoassay methods have been reported for the detection of botulinum toxins including radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). A promising new method for the detection of bacterial spores and toxins uses a biosensor based on electrochemi luminescence (Gatto-Menking et al. 1995). A mouse bioassay is also available for detection of botulism toxins and, more recently, matrix assisted laser desorption ionisation–time of flight mass spectrometry (MALDI-TOF-MS) and LC-ESI-MS/MS have been used for detection and quantification of the botulinum toxins (Barr et al. 2005).Generally applicable analytical methods for the identification and quantification of tetanus toxin have not been reported (Cherington et al. 1995) but an ESI-MS/MS method has recently been reported for detecting tetanus toxin in bacterial cultures (vanBaar et al. 2002).