132 - Clostridium

Summary

Introduction

The genus Clostridium contains many species of bacteria that cause human diseases. These bacteria produce some of the most deadly toxins ever discovered. Distinctive infections include botulism, tetanus, gas gangrene, and food poisoning from Clostridium perfringens. With few exceptions, clostridia are obligate, anaerobic, spore-forming bacilli that are ubiquitous in the environment, in soil and marine sediment. Although a member of the Clostridium genus, Clostridium difficile is discussed separately (Chapter 51, Antibiotic-associated diarrhea).

Botulism

Botulism is a rare but potentially fatal disease caused by Clostridium botulinum bacteria, which produce botulinum toxin, one of the most potent bacterial toxins ever described. It can be classified into four categories which reflect the mode of acquisition: foodborne botulism, infant and adult enteric botulism, wound botulism, and inhalational botulism. A recent category, iatrogenic botulism, has also been described in patients who have received botulinum toxin injections. All modes of acquisition can lead to the clinical syndrome of botulism, which manifests as symmetric flaccid paralysis of the voluntary musculature.

The word botulism is derived from the latin word botulus, which means sausage, and is a reference to an early investigation of “sausage poisoning” in a southern German town in which affected patients developed gastrointestinal and neuromuscular symptoms. This investigation is believed to be the first described outbreak of foodborne botulism.

There are eight strains of C. botulinum that are classified according to the type of toxin they produce. Of the eight toxin types, only types A, B, E, and occasionally F cause human disease. The spores are heat-resistant and able to survive at 100°C for several hours. In contrast to the spores, the toxins are heat-labile and are readily denatured by heating to temperatures above 80°C.