Clostridium perfringens

Hello. My name is Dr. Sarah Fouch, and within this session, we will be considering Clostridium perfringens. We will briefly discuss the clinical conditions that this organism is associated with, and also the virulence factors that it can produce in order to make it a successful pathogen.

When we think about Clostridium perfringens, this is a large rectangular gram-positive bacillus. It's non-motile, so it has no flagella. When we culture this organism using routine culture, the colonies are quite large. There are also areas of haemolysis, so the organism is able to break down the red blood cells. This enables the organism to grow rapidly in the tissue. As with other organisms that we have discussed, when we think about some of the clinical conditions that Clostridium perfringens can cause, these are very much toxin mediated. There are a number of different toxins that Clostridium perfringens can produce, and we will look at those in the coming slides. When we think about Clostridium perfringens, we have five types. We have A, B, C, D, and E. Most clinical infections that will present are caused by type A.

Let's think about the different clinical conditions that are associated with Clostridium perfringens. Type A is very much associated with gas gangrene or other types of soft tissue infection. It can also cause food poisoning. If we think about gas gangrene, this is a severe infection, and the patient is acutely unwell. In order for this organism to achieve this level of infection, it needs to elicit all of its virulence factors. When we think about gas gangrene, this normally happens after a traumatic event. A patient may have had a nasty accident. They may have a dirty wound. That wound has come in contact with the environment, and actually, Clostridium perfringens could have been surviving within that environment. We can also have patients that have gas gangrene after surgery, and if the wound has become infected, then obviously it will initially cause a superficial infection and then the patient will have quite a nasty gas gangrene that's affecting the deeper layers of the tissue. If we think about the longer term effects of this type of infection, actually, this is a very nasty, deep skin infection, and the patient can have necrosis of the muscle, so we can have a really extensive infection and the patient is at risk of going into shock. That can result in multiple organs being affected. Very similar type of condition to necrotising fasciitis, but necrotising fasciitis doesn't have the gas within the tissue that we see with a Clostridium perfringens infection. Unfortunately, if all of this is going on, the patient can go into renal failure and also have problems with their other organs as well. You can see that gas gangrene, actually, has quite a high mortality rate, and as I've just said, you can actually see the gas within the tissue, it almost looks a little like bubbles within the tissue. We've actually got a picture of a patient here, where you can see that area of infection. If you touch it, you can, actually, feel the gas within that area.