Chapter 45 - Clostridium botulinum and associated neurotoxins

Abstract

Clostridium botulinum is a gram-positive, obligate anaerobic, spore-forming bacterium renowned for the production of botulinum neurotoxins (BoNTs) during sporulation (with the capacity to block the acetylcholine release in neurons) and the causation of a rare but severe flaccid paralytic disease called botulism (manifesting as foodborne botulism, infant botulism, adult intestinal toxemia, wound botulism, and iatrogenic botulism). Among seven main BoNT serotypes (A–G), serotypes A, B, E, and occasionally serotype F are implicated in human illness, while serotypes C and D contribute to animal botulism. Current diagnosis of human botulism relies on observation of typical clinical signs and symptoms in combination with exposure history; further laboratory confirmation is achieved through culture isolation, and detection of related genes and toxins. Due to botulism’s rapid progression and potential high mortality, prompt implementation of supportive care and antitoxin therapy is necessary to limit the damage of this disease. In spite of their extreme toxicity (with a lethal dose of ~1ng/kg in humans) and their potential as a biowarfare agent, BoNTs are increasingly harnessed for treating an expanding range of clinical diseases, because of their high specificity, low side-effects, and durable effect (3–6 months) after a single application.