Clostridium tetani

Hi, everyone. My name is Dr. Sarah Fouch. Welcome to this short recording, where we will be considering Clostridium tetani. As we work through this recording, we will consider the symptoms associated with tetanus and the virulence factors produced by Clostridium tetani to cause the symptoms that patients will experience.

Let's consider Clostridium tetani. Now, when we think about Clostridia, the two we are most worried about are Clostridium tetani and Clostridium botulinum. If we think about the two types of Clostridia, they are associated with paralysis. Clostridium botulinum will allow the muscle to relax. This will cause a flaccid paralysis; whereas, Clostridium tetani has completely the opposite effect and can cause a very spastic paralysis. Now, we don't see that many cases of Clostridium tetani in developed countries, and that's because we have a vaccination. Now, if a patient experiences a dirty wound, they have an accident, and they have come into contact with environmental substances, they are then taken to the accident and emergency department. The first thing the clinician will ask you is when did you last have your tetanus vaccination. Now, this is really important because actually, this vaccination will keep the individual from contracting a Clostridium tetani infection. We need to remember that, actually, in other countries, tetanus vaccinations are not as easy to come by, and actually, Clostridium tetani can cause a high number of deaths across the world. Now, here we have a Gram stain of Clostridium tetani. The first thing you might say to me is, well, on the slides you've put that it's a Gram-positive organism. However, looking at that image, it looks Gram-negative. Why is that the case? Again, you might be thinking, well, you've told me it's a Bacillus, but they don't look like a Bacillus. They look like little tennis rackets. Well, they will stain Gram-negative because they are starting to form their spores. Now, as they start to sporulate, the bacterial cell wall will start to break down. Now, if the bacterial cell wall starts to break down, that thick peptidoglycan will not hold on to the crystal violet; very often, Clostridium tetani will stain Gram-negative. Now, they are susceptible to oxygen. They do not like the oxygen, and this is due to them being an obligate anaerobic organism. As soon as they come into contact with too much oxygen, they will start to form spores. Again, the spores are very good. They are an excellent virulence factor because they enable the Clostridium tetani to live in the soil and also in the GI tract of animals for prolonged periods of time. Now I've also said here that these are Saprophytic organisms. This means they can live off of dead or dying material, so they are able to survive and gain their virulence and any nutrients that they require from dead or dying matter. Now, Clostridium tetani is a motile organism. It possesses flagellum and is able to move. Now, individuals who are most at risk are children, the elderly, and those with reduced immunity. Now, when we think about all of the different organisms we've discussed in this series of recordings, these demographics of patients are at risk of most infections. Young children their immune system is just starting to become active. Elderly patients, their immune system is just starting to wind down. When we think about those patients with no immunity or reduced immunity, they are at increased risk of any type of infection. There's no difference with Clostridium tetani. When we think about patients who are at risk, it's those doing manual work- working in the environment. If they have an accident and it's a dirty wound, they have an increased risk of gaining Clostridium tetani infection, and that's why the vaccination is so important.