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'''Clostridium perfringens''' (formerly known as ''Clostridium welchii'') is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus ''Clostridium''. Sherris Medical Microbiology, Ryan KJ; Ray CG (editors), , , McGraw Hill, 2004, ISBN 0-8385-8529-9 ''C. perfringens'' is ubiquitous in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. Virtually every soil sample ever examined, with the exception of the sands of the Sahara, has contained ''C. perfringens''.

Contents

Infection characteristics

Food poisoning

Colony characteristics

References

External links

Infection characteristics

''C. perfringens'' is commonly encountered in infections as a benign component of the normal flora. Clostridia: Sporeforming Anaerobic Bacilli. ''In:'' Barron's Medical Microbiology ''(Barron S ''et al'', eds.), Wells CL, Wilkins TD, , , Univ of Texas Medical Branch, 1996, (via NCBI Bookshelf) ISBN 0-9631172-1-1 In this case, its role in disease is minor. Infections due to ''C. perfringens'' show evidence of tissue necrosis, bacteremia, emphysematous cholecystitis, and gas gangrene, which is also known as clostridial myonecrosis. The toxin involved in gas gangrene is known as α-toxin, which inserts into the plasma membrane of cells, producing gaps in the membrane which disrupt normal cellular function. Oxford Textbook of Medicine, Warrell et al., , , Oxford University Press, 2003, ISBN 0-19-262922-0
The action of ''C. perfringens'' on dead bodies is known to mortuary workers as tissue gas and can only be halted by embalming.

Food poisoning

Some strains of ''C. perfringens'' produce toxins which cause food poisoning if ingested. In the United Kingdom and United States they are the third most common cause of food-borne illness, with poorly prepared meat and poultry the main culprits in harboring the bacterium. Oxford Textbook of Medicine, Warrell et al., , , Oxford University Press, 2003, 0-19-262922-0 The clostridial enterotoxin mediating the disease is often heat-resistant and can be detected in contaminated food and feces. Current Medical Diagnosis & Treatment, Adelman et al., , , McGraw Hill, 2006, ISBN 0-07-147177-4
Incubation time is between 8 and 16 hours after ingestion of contaminated food. Manifestions typically include abdominal cramping and diarrhea - vomiting and fever are unusual. The whole course usually resolves within 24 hours. Very rare, fatal cases of clostridial necrotizing enteritis have been known to involve "Type C" strains of the organism, which produce a potently ulcerative β-toxin.
It is likely that many cases of ''C. perfringens'' food poisoning remain sub clinical, as antibodies to the toxin are common amongst the population. This has led to the conclusion that most, if not all, of the population has experienced food poisoning due to ''C. perfringens''. Oxford Textbook of Medicine, Warrell et al., , , Oxford University Press, 2003, 0-19-262922-0

Colony characteristics

On blood agar plates, ''C. perfringens'' grown anaerobically produces β-haemolytic, flat, spreading, rough, translucent colonies with irregular margins. A Nagler agar plate, containing 5-10% egg yolk, is used to presumptively identifiy strains which produce α-toxin, a diffusible lecithinase which interacts with the lipids in egg yolk to produce a characteristic precipitate around the colonies. One half of the plate is inoculated with antitoxin to act as a control in the identification.

References

External links

★ Pathema-''Clostridium'' Resource