Clostridia

Clostridia include bacterial species that are responsible for generating some of the most potent toxins known to humans. They are obligate, anaerobic, spore-forming bacilli that live in soil and the intestinal tract of animals and man. Of the 83 clostridia strains, approximately 30 are clearly or potentially pathogenic. Distinctive types of infection have been associated with certain species of Clostridium : gastrointestinal illness with Clostridium perfringens and Clostridium difficile ; neurologic syndromes with Clostridium botulinum and Clostridium tetani ; focal suppurative infections, myonecrosis, and gas gangrene with Clostridium perfringens, Clostridium novyi, Clostridium septicum, Clostridium histolyticum, Clostridium bifermentans , and Clostridium fallax ; and bacteremia with Clostridium perfringens, Clostridium septicum, Clostridium sordellii , and Clostridium tertium . BOTULISM Pathogenesis Botulism is a neuroparalytic illness caused by a neurotoxin produced from the anaerobic, spore-forming bacterium C. botulinum . The disease can be categorized as (1) foodborne, (2) wound, (3) intestinal (infant botulism), and (4) inhalational botulism, a human-made form from the inhalation of aerosolized botulism toxin. Fewer than 200 cases of all forms of botulism are reported annually in the United States. The eight strains (A, B, C1, C2, D, E, F, and G) of C. botulinum have separated on the antigenic specificities of their toxins. Of these antigenic types, type A is the most common cause of foodborne botulism. Only types A, B, E, and F cause illness in humans.