CLOSTRIDIUM BOTULINUM

'''Clostridium botulinum''' is a bacterium that produces the toxin ''botulin'', the causative agent in botulism. Sherris Medical Microbiology, Ryan KJ; Ray CG (editors), , , McGraw Hill, 2004, ISBN 0838585299 It is included in the genus ''Clostridium'', a major group of Gram-positive forms. ''C. botulinum'' was first recognized and isolated in 1896 by Emile van Ermengem and is commonly found in soil.
These rod-shaped organisms grow best in low-oxygen conditions. They form spores that allow them to survive in a dormant state until exposed to conditions that can support their growth. Brock Biology of Microorganisms, Madigan M; Martinko J (editors)., , , Prentice Hall, 2005, ISBN 0131443291

Contents

Subtypes

External links

References

Subtypes

Each of the seven subtypes of ''C. botulinum'' produces a different botulin toxin. Botulism and ''Clostridium botulinum'' ''in:'' Baron's Medical Microbiology ''(Baron S ''et al'', eds.), Wells CL, Wilkins TD, , , Univ of Texas Medical Branch, 1996, (via NCBI Bookshelf) ISBN 0-9631172-1-1 These are labeled with letters and are called ''A'' to ''G'' types. Types ''C'' and ''D'' are not human pathogens. A "mouse protection" test determines the type of ''C. botulinum'' present using monoclonal antibodies.
In the United States, outbreaks are primarily due to types ''A'' or ''B'', which are found in soil, or type ''E'', which is found in fish. Optimum temperature for types ''A'' and ''B'' is 35-40 °C. Minimum pH is 4.6. It takes 25 min at 100 °C to kill these types. Optimum temperature for type ''E'' is 18-25 °C. Minimum pH is 5.0. It takes about 0.1 minute at 100 °C to kill type ''E'' ''C. botulinum''.
''C. botulinum'' strains that do not produce a botulin toxin are referred to as ''Clostridium sporogenes''^[1]. The species are otherwise phylogenetically indistingishable, and ''C. sporogenes'' is often used as a model for the toxic subtypes.
''Clostridium botulinum'' is also used to prepare Botox, used to selectively paralyze muscles to temporarily relieve wrinkles. It has other "off-label" medical purposes, such as treating severe facial pain, such as that caused by trigeminal neuralgia.
Botulin toxin produced by ''Clostridium botulinum'' is often believed to be a potential bioweapon as it is so potent that it takes less than 1 microgram to kill a person, a drop could kill 100,000 people, and 1 pound of it can kill the entire human population, though contact is uncommon.
Clostridium botulinum is a soil bacterium. The spores can survive in most environments and are very hard to kill. They can survive the temperature of boiling water at sea level, thus many foods are canned with a pressurized boil that achieves an even higher temperature, sufficient to kill the spores.
Growth of the bacterium can be prevented by high acidity, high ratio of dissolved sugar, high levels of oxygen, or very low levels of moisture. For example in a low acid, canned vegetable such as green beans that are not heated hot enough to kill the spores (ie. a pressurized environment) may provide an oxygen free medium for the spores to grow and produce the toxin. On the other hand, tomatoes or tomato sauce are sufficiently acidic to prevent growth; even if the spores are present, they pose no danger to the consumer. Honey, corn syrup, and other sweeteners may contain spores but the spores cannot grow in a highly concentrated sugar solution; however, when a sweetener is diluted in the low oxygen, low acid digestive system of an infant, the spores can grow and produce toxin. As soon as infants begin eating solid food, the digestive juices become too acidic for the bacterium to grow.

External links

★ Pathema-''Clostridium'' Resource

References

1. Judicial Commission of the International Committee on Systematic Bacteriology (1999) Rejection of ''Clostridium putrificum'' and conservation of ''Clostridium botulinum'' and ''Clostridium sporogenes'' Opinion 69. International Journal of Systematic Bacteriology. 49, 339.