|Photomicrograph of gram-positive Clostridium perfringens bacilli.|
Veillon & Zuber 1898
Hauduroy et al. 1937
Clostridium perfringens (formerly known as C. welchii, or Bacillus welchii) is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present 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. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycollate medium.
C. perfringens is the third most common cause of food poisoning in the United Kingdom and the United States though 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, 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 that disrupt normal cellular function. C. perfringens can participate in polymicrobial anaerobic infections. Clostridium perfringens is commonly encountered in infections as a component of the normal flora. In this case, its role in disease is minor.
In the United Kingdom and United States, C. perfringens bacteria are the third most common cause of foodborne illness, with poorly prepared meat and poultry, or food properly prepared but left to stand too long, the main culprits in harboring the bacterium. The clostridium perfringens enterotoxin (CPE) mediating the disease is heat-labile (inactivated at 74 °C (165 °F)). It can be detected in contaminated food (if not heated properly), and feces. Incubation time is between six and 24 (commonly 10-12) hours after ingestion of contaminated food.
Since C. perfringens forms spores that can withstand cooking temperatures, if cooked food is let stand for long enough, germination can ensue and infective bacterial colonies develop. Symptoms typically include abdominal cramping, diarrhea; vomiting and fever are usual. The whole course usually resolves within 24 hours. Very rare, fatal cases of clostridial necrotizing enteritis (also known as pigbel) have been known to involve "Type C" strains of the organism, which produce a potently ulcerative β-toxin. This strain is most frequently encountered in Papua New Guinea.
Many cases of C. perfringens food poisoning likely remain subclinical, as antibodies to the toxin are common among the population. This has led to the conclusion that most of the population has experienced food poisoning due to C. perfringens.
Clostridium perfringens is the most common bacterial agent for gas gangrene, which is necrosis, putrefaction of tissues, and gas production. It is caused primarily by Clostridium perfringens alpha toxin. The gases form bubbles in muscle (crepitus) and the characteristic smell in decomposing tissue. After rapid and destructive local spread (which can take only hours), systemic spread of bacteria and bacterial toxins may cause death. This is a problem in major trauma and in military contexts. C. perfringens grows readily on blood agar plate in anaerobic conditions, and often produces a double zone of beta hemolysis.
Research published in 2014 suggested that a strain of C. perfringens might be implicated in multiple sclerosis (MS). Tests in mice found that a toxin made by a rare strain of C. perfringens caused MS-like damage in the brain, and earlier work had identified this strain of C. perfringens in a human with MS. MS patients were found to be ten times more immune-reactive to the epsilon toxin than healthy people.
C. perfringens can be diagnosed by Nagler's Reaction where the suspect organism is cultured on an egg yolk media plate. One side of the plate contains anti-alpha-toxin, while the other side does not. A streak of suspect organism is placed through both sides. An area of turbidity will form around the side that does not have the anti-alpha-toxin, indicating uninhibited lecithinase activity.
If suspected on clinical grounds, treatment should begin without waiting for lab results. Traumatic wounds should be cleaned. Wounds that cannot be cleaned should not be stitched shut. Penicillin prophylaxis kills many clostridia and is thus useful for dirty wounds and lower leg amputations. A high infectious dose is required; the carrier state persists for several days.
Food poisoning incidents
On May 7, 2010, 42 residents and 12 staff members at a Louisiana state psychiatric hospital experienced vomiting, abdominal cramps, and diarrhea. Within 24 hours, three patients had died. The outbreak was linked to chicken which was cooked a day prior to being served and was not cooled down according to hospital guidelines. The outbreak affected 31% of the residents of the hospital and 69% of the staff who ate the chicken. It is unknown how many of the affected residents ate the chicken.
In May 2011, a man died after allegedly eating food contaminated with the bacteria on a transatlantic American Airlines flight. The man's wife and daughter are suing American and LSG Sky Chefs, the German company that prepared the inflight food.
In December 2012, a 46-year-old woman died two days after eating a Christmas Day meal at a pub in Hornchurch, Essex, England. She was among about 30 people to fall ill after eating the meal. Samples taken from the victims contained C.perfringens. The woman's husband said that he intended to take legal action over his wife's death. 
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- "Multiple sclerosis 'linked to food bug'". BBC. 29 January 2014. Retrieved 29 January 2014.
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- Mohn, Tanya. "Overhead Bin - Passenger dies in-flight, family says airline to blame". Overheadbin.msnbc.msn.com. Retrieved 2012-02-13.
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- Clostridium perfringens genomes and related information at PATRIC, a Bioinformatics Resource Center funded by NIAID
- Pathema-Clostridium Resource