Caister Academic Press


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A review of Clostridium.


The genus Clostridium represents a heterogeneous group of anaerobic spore-forming bacteria, comprising prominent toxin-producing species, such as C. difficile, C. botulinum, C. tetani and C. perfringens, in addition to well-known non-pathogens like solventogenic C. acetobutylicum. In the last decade several clostridial genomes have been deciphered and post-genomic studies are currently underway. The advent of newly developed, genetic manipulation tools have permitted functional-based and systems biology analyses of several clostridial strains.

Clostridium perfringens Enterotoxin

Adapted from Sameera Sayeed, Susan L. Robertson, Justin A. Caserta and Bruce A. McClane in Clostridia: Molecular Biology in the Post-genomic Era
Clostridium perfringens enterotoxin (CPE) causes the intestinal symptoms of a common food-borne illness and ~5-15% of all antibiotic-associated diarrhea cases. In food poisoning isolates, the enterotoxin gene (cpe) is usually present on the chromosome, while cpe is carried by conjugative plasmids in antibiotic-associated diarrhea isolates. CPE action involves its binding to claudin receptors, oligomerization/prepore formation, and prepore insertion to form a functional pore that kills cells by apoptosis or oncosis. The C-terminal half of CPE mediates receptor binding, while its N-terminal half is required for oligomerization. CPE/CPE derivatives are being explored for cancer therapy/diagnosis and improved drug delivery.

Clostridium Food Pathogens

Adapted from John S. Novak, Michael W. Peck, Vijay K. Juneja and Eric A. Johnson in Foodborne Pathogens: Microbiology and Molecular Biology
Clostridium: Clostridium botulinum produces extremely potent neurotoxins that result in the severe neuroparalytic disease, botulism. Although of lower lethality, the enterotoxin produced by Clostridium perfringens, during sporulation of vegetative cells in the host intestine, still results in debilitating acute diarrhea and abdominal pain. Sales of refrigerated, processed foods of extended durability including sous-vide foods, chilled ready-to-eat meals, and cook-chill foods have increased over recent years. As a result of conditions accommodating growth, anaerobic spore-formers have been identified as the primary microbiological concerns in these foods. Heightened awareness over intentional food source tampering with botulinum neurotoxin has arisen with respect to genes encoding the toxins that are capable of transfer to nontoxigenic clostridia. Similarly, enterotoxin produced by Clostridium perfringens and the genomic location of the cpe gene has epidemiologic significance for understanding the capability to cause foodborne disease in humans. The unique characteristics and virulence factors of Clostridium botulinum and Clostridium perfringens make them foodborne hazards in the food supply. The susceptibility of these bacterial spore-formers to physical and chemical agents is examined as well as recommended control measures. This information is useful in developing molecular strategies to study virulence genes and their regulation as a means to safer foods.

Further reading