Clostridium perfringens

Clostridium perfringens is a gram-positive, sporulating , aerotolerant bacterium.

Occurence
The vegetative cell has the shape of a rod, the thickness of which is over 1 μm and the length ranges from 2 to 10 μm. Spores are oval, thermoresistant , paracentral, occur commonly in our environment, such as soil, waste and easily contaminate food (especially meat). Sporulation takes place in the intestine, never in the affected tissue. Clostridium perfringens produces many biologically active substances, including toxins and enterotoxin. According to the type of toxin produced, it is divided into five groups (A-E). Clostridium perfringens is part of the normal intestinal microflora of humans and animals.

Toxins
All types of Clostridium perfringens produce α toxin (phospholipase C, lecithinase), which has lethal and necrotizing effects. Other effects of toxins include:
 * cytotoxicity
 * cell membrane lysis and hemolysis
 * increase capillary permeability
 * lowering blood pressure
 * damage to enterocytes and leukocytes, as well as the heart , kidneys and blood vessels

Types A, B, D form a thermolabile enterotoxin in food, the spores of which are thermoresistant and can survive even boiling.

Pathogenesis
Clostridium perfringens is one of the most common human pathogens. Presence in the human body can cause histotoxic infections, gas gangrene, cellulitis. However, Clostridium perfringens is most often the cause of intestinal diseases (colic, watery diarrhea, enteritis, enterotoxemia). In colic and watery diarrhea, the incubation period is 8-14 hours after eating contaminated food, the symptoms (diarrhea, convulsions, abdominal pain) persist for about 24 hours. Nausea, fever and vomiting are present minimally.

Cultivation
Due to the fact that Clostridium perfringens belongs to aerotolerant bacteria, its cultivation is relatively easy. It hydrolyzes gelatin due to a number of saccharolytic and proteolytic enzymes. Type A forms a double zone of hemolysis, while the outer one (with incomplete hemolysis) is given by the action of phospholipase C (toxin α). A zone of opalescence is evident on the yolk agar, which is also caused by phospholipase C.

Diagnostics
To diagnose diseases caused by Clostridium perfringens, clinical signs, an epidemiological history and microbiological examination must be assessed. In the case of soft tissues, excision is taken from the wound, exudate or part of the damaged tissue.

Summary
https://www.youtube.com/watch?v=h_A8yVY1kBg

Source

 * PubMed: Toxin plasmids of Clostridium perfringens
 * Nejm: Bacterial Diarrhea
 * NCBI:Clostridia: Sporeforming Anaerobic Bacilli