Clostridium perfringens (formerly known as C. welchii, or Bacillus welchii) is a Gram-positive bacterium. C. perfringens is third-most common cause of foodborne illness, alongside norovirus, Salmonella, Campylobacter, and Staphylococcus aureus. However, it can sometimes be ingested and cause no harm.
Infections due to C. perfringens show evidence of tissue necrosis, bacteremia, emphysematous cholecystitis, and gas gangrene, also known as clostridial myonecrosis.
The toxin involved in gas gangrene is α-toxin.
Poorly prepared meat and poultry, or food properly prepared, but left to stand too long, the main culprits in harboring the bacterium. Contaminated meats in stews, soups, and gravies are usually responsible for outbreaks. Deaths due to the disease are rare and mostly occur in elderly and people who are predisposed to the disease.
C. perfringens poisoning can lead to enteritis necroticans or clostridial necrotizing enteritis in protein-deficient diet, unhygienic food preparation, sporadic feasts of meat (after long periods of a protein-deficient diet), diets containing large amounts of trypsin inhibitors (sweet potatoes), areas prone to infection of the parasite Ascaris (produces a trypsin inhibitor). This disease is contracted in populations living in New Guinea, parts of Africa, Central America, South America, and Asia.