Hello everyone, today I will like us to look at microbiology and infectious disease, and on that note, we will take a look at the microbiology of Clostridia. While some people do not know the genus name Clostridium, they must have heard the word Tetanus. Sit back and let us share with ourselves, what we should know about Clostridium.
Clostridia has four major clinically important species which are Clostridium Botulinum, Perfringens, difficile, and tetani. Clostridium Botulinum causes Botulism, Clostridium Tetani causes Tetanus, Clostridium perfringens causes myone necrosis and food poisoning, and Clostridium Pseudomembranous colitis. For a quick explanation, Clostridium is gram-positive spore-forming rod bacteria that are mostly strictly anaerobic and are mostly motile such as C.botulinum, C.tetani, and C.defficile but a non-motile Clostridium is C.perfringens. These aren't the only specie of Clostridium, but we are discussing these ones in this post.
Clostridium tetani is responsible for tetanus which is from the toxin Tetanus toxin which causes spasms as it inhibits GABA causing spastic paralysis. Clostridium botulinum on the other hand causes flaccid paralysis, as it inhibits the release of acetylcholine from the pre-synaptic neuron. Clostridium difficile which is causes pseudomembranous colitis which is caused by enterotoxin and cytotoxin. Clostridium perfringes is ubiquitous and it can be contaminated by the bacteria from the soil coming in contact with the wound, causing myonecrosis and gas gangrene. To treat this, the patient is placed in an aerobic environment, remember that the bacteria is anaerobic.
Clostridium creates an endospore which is needed during unfavorable conditions. The endospore includes a complete copy of the chromosome, essential proteins and ribosomes, and calcium bonded to dipiclonic acid. The Spore contains the DNA of the bacteria, the cytoplasm, the inner membrane, the cell wall which is made up of thick peptidoglycan, outer protein coat made of keratin. The spore protects the bacteria's DNA from chemicals, heat, and enzymes that could destroy the bacteria. It also enables clinicians to identify the bacteria when viewing in the lab. Clostridium is unable to reduce sulfate to sulfite and not all clostridia are gram-positive, species such as Clostridium ramosum is a gram-negative bacterium. Some species are also aerobic and such as Clostridium histolyticum and not all clostridium readily make spores such as Clostridium perfringens.
Let's take the species one after the other and discuss Clostridium tetani. As I said, it is a gram-positive rod bacteria that causes tetanus with spasms that had to do with locked jaws or trismus. It is caused by the toxin tetanospasmin which inhibits GABA causing an excitatory effect leading to spasticity or spastic paralysis. It is ubiquitous in soil, water, and sewage, and it is a strict anaerobe causing it to be very difficult to grow in the lab (Tetanolysin). The toxins Oxygen Labile hemolysin, and heat-labile neurotoxin (Tetanospasmin). Tetanolysinos inhibited and killed in the body by the oxygen in the body but Tetanospasmin isn't. It is an exotoxin with A and B subunits with A being Active or enzymic activity with the enzyme Zinc endopeptidase, while B is for bidding, which binds with the cell receptors and leads to spasms in the jaw, hyperextension of the back, and facial muscle, etc. When the AB toxin is cleaved, the B toxin with a Cooh terminus that binds with the Glycoprotein and the sialic acid receptor. In the axon of the motor neuron, it will be internalized in the neuron where it will travel towards the soma of the motor neuron where it is acidified. The active part of the toxin passes through the cell membrane to the cytosol where it begins to act with zinc metalloprotease to break down snare protein which is responsible for the transmission and release of neurotransmitters into their synaptic cleft thereby inhibiting GABA from being produced. The creation of a new axon knob that contains new snare protein can help in recovering from tetanus.