In this class I try quite hard not to present an overwhelming variety of different diseases and microbes. But here on the blog anything goes. So for those of you who want to learn about more microbes, meet the Clostridiums.
First up, we've already mentioned. Clostridium perfringens as the causative agent of gas gangrene - a major cause of death in World War 1.
You might also have heard of Clostridium botulinum, or at least of the disease it causes - botulism. Botulism is a paralytic food poisoning that is fortunately rare. The bacteria grow on food and cause harm in people as we digest a toxin produced by the bacteria. The neurotoxin is one of the most powerful toxins known to man, a single microgram is lethal. It is also used (in minute doses!) in the cosmetic treatment known as Botox.
Clostridium tetani is the causative agent of tetanus. The symptoms, muscle spasms and difficulty swallowing are caused by a neurotoxin produced by the bacteria. Infection generally occurs through wound contamination, and often involves a cut or deep puncture wound. Infection can be prevented by immunization, and this is often successful even if given after the wound occurs. Which is why it's a good idea to get a tetanus shot after a deep cut or puncture wound. If you wait to see if an infection develops it is too late for immunization to be much use.
The final member of our happy little Clostridium family is Clostridium difficile. C. difficile, or just C. diff. is the latest, greatest threat in nosocomial infections and there have been numerous outbreaks lately. Try a google news search on Clostridium difficile to see where the latest outbreak is (Canada apparently). C. diff is an interesting bacteria because it is found as a natural part of the gut flora in a small fraction of people, usually with no problems. But if the usual gut flora is eradicated with broad spectrum antibiotics C.diff can greatly increase in numbers and release toxins that cause severe diarrhoea and death in some cases. Some new strains appear to be producing much more toxin. Hospitals are very good places to find people taking broad spectrum antibiotics and, apparently, are good at spreading C.diff around as well. There was an MSNBC article with the subhead ‘C. diff’ rivals MRSA as the next deadly bacteria threat, experts say' in May of this year.