Overview
The Clostridia group encompasses Gram-positive, anaerobic bacilli which are implicated in disorders such as botulism, tetanus, bowel infection, and gas gangrene. Clostridium difficile was reclassified in 2016 to Clostridioides difficile due to differences in its characteristics compared to other Clostridia.
Clostridium botulinum
Clostridia botulinum causes botulism due to its production of the botulinum toxin. This is a neurotoxin that interferes with the release of acetylcholine at the presynaptic end of a neuromuscular junction, causing acute paralysis. It is associated with canned foods and honey.
Clostridium tetani
Clostridium tetani causes tetanus due to the production of the tetanospasmin toxin. This is a neurotoxin which blocks the release of inhibitory neurotransmitters (e.g. GABA), resulting in excess muscle contraction and impaired relaxation. It is found in soil and in the gastrointestinal tracts of animals.
Clostridioides difficile
Clostridioides difficile can cause a bowel infection and pseudomembranous colitis, often after the use of broad-spectrum antibiotics (e.g. cephalosporins) and clindamycin. It can be a normal inhabitant of the bowel flora.
Clostridium perfringens
Clostridium perfringens causes gas gangrene, a severe infection of the skin and soft tissue usually due to adjacent wounds contaminated with it. It produces a toxin called lecithinase (a phospholipase), which causes muscle necrosis and haemolysis.
