An anaerobic bacterium is a branch of bacteria that doesn’t grow or live in the presence of oxygen. These bacteria strive in the gastrointestinal tract of humans (also where they are most commonly found). They cause conditions such as perforation of the bowel, diverticulitis and appendicitis.
In this assignment we will be looking at the following anaerobic bacteria:
1. C. Tetani (tetanus)
2. C. Botulinium
3. C. Perfringens
4. Other clostridial diseases
5. Non-spore forming anaerobes
Characteristics of Clostridia:
Clostridium is a genus that falls under Gram-positive bacteria and includes many important human pathogens. This includes the botulism causative agent and one of the important causes of diarrhoea, Clostridium difficile. These are anaerobes that are capable of producing endospores. The ordinary reproducing cells of Clostridium are called the vegetative form and they are rod-shaped. Clostridium endospores have a specific bottle or bowling pin shape which distinguishes them from other forms of bacterial endospores, which are usually oval in shape. Clostridium species occupy intestinal tracts of animals and humans as well as soil. Clostridium is a normal occupant of a healthy lower reproductive tract in women.
Clostridia contains many sub categories, these will be discussed now.
1. C. tetani (Tetanus)
C. tetani is characterized by convulsive spasms and cramps of skeletal muscles. It is also associated with muscle stiffness which usually involves the neck and jaw (lockjaw), which then becomes generalised. The most common initial symptom is signs of spasms of the neck muscles as well as that of the jaw “lockjaw”.
Tetanus symptoms include:
Muscle spasms (often in the stomach), painful muscle stiffness all over the body, difficulty swallowing, fast heart rate, change in blood pressure, jerking or staring (seizures), jaw cramping, headache, sweating and fever.

Tetanus is an acute disease that is caused by an exotoxin. This exotoxin is produced by the bacterium Clostridium tetani and is often fatal. This exotoxin is called tetanospasmin.
The bacteria would usually enter the body through a wound. Without the presence of oxygen or low oxygen concentration present, the bacterial spores would germinate. Toxins would be produced and diffuse into the lymphatics and blood. The toxin would affect many sites within the central nervous system (CNS). These sites would include the spinal cord, brain, the peripheral motor end plates as well as the sympathetic nervous system. The typical clinical symptoms are caused when the toxins affects or interferes with the release of neurotransmitters within the body. This blocks action potentials from firing. This leads to uncontrolled muscle spasms and sometimes seizures as the autonomic nervous system would be affected.
We can identify many different forms of tetanus, they are: Local, generalised and neonatal. The tetanus virus is primarily diagnosed through the patient’s clinical symptoms (e.g. painful back, muscle spasms, muscle cramps, generalized cramps of the arcuate curvature of the body etc.) and also through a microbiological diagnosis.

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Tetanus is a very serious bacterial infection. This bacteria exists in manure, soil as well as other environmental agents. A person that receives a puncture wound from a contaminated object can also develop the infection. It can be fatal. Thus one method of prevention would be to try your best to avoid scrapes, burns and puncture wounds. Another very successful method would be to get vaccinated.

A tetanus vaccine is one that is given routinely to children as part of their tetanus and diphtheria shot. It is given at the following months: 2, 4, 6, 15-18 months and then 4-6 years of age. A booster would usually be given at the age of 11 and 18 and another would be given every 10 years thereafter.

Wounds obtained should be cleaned rigorously to prevent infection. A wound that is most likely to develop a tetanus infection would be defined as the following:
1. A burn wound that requires surgery and was left untreated for more than 6 hours.
2. Any puncture wound that was in contact with soil or manure.
3. A burn that has removed quite a lot of tissue.
4. Fractures (Serious ones) where bone is exposed to infection possibilities (eg. Compound fractures)
Any patient that has received a wound that is listed above would need to get a tetanus immunoglobulin, or otherwise known as a “TIG”, as soon as they can. This includes whether they were vaccinated or not. TIG contains specific antibodies that would destroy Clostridium tetani. It would be injected into a vein and would provide protection against the bacteria immediately. TIG is purely a short term resolve and does not replace any long term vaccinations. It is safe for pregnant or breast feeding mothers as well.
Penicillin could also be prescribed as this antibiotic would stop the bacteria from multiplying and secreting its’ neurotoxin which would cause muscle stiffness and muscle spasms. People that are allergic to penicillin would be given an alternative, this alternative is called tetracycline.

When treating muscle stiffness and spasms, people will be prescribed the following:

Muscle relaxants:
Baclofen is a good example. It suppresses all nerve signals travelling from the brain to the spinal cord which would result in an overall decreased muscle tension.

Diazepam (otherwise known as Valium) is a good example. It relaxes muscles to stop muscle spasms, alleviate anxiety, and would also work as a type of sedative.
A person that has tetanus will need to consume a lot of calories as they would have an increased muscle activity.
If tetanus prone wound is very big, the doctor can decide whether or not they should surgically remove the damaged and infected muscle (as much of it as possible. This is known as debridement.
Some people may need the assistance of a ventilator to support with respiration if their respiratory muscles or vocal cords are affected by the bacteria.

2. C. Botulinium
There are 3 types of botulism, they are:
1. Foodborne botulism
2. Wound botulism
3. Infant Botulism
Foodborne botulism:
Symptoms would typically start around 12 to 36 hours after the food is ingested and the toxin is absorbed by the body. Depending on the quantity of the toxin that was consumed, the symptoms expressed may show themselves within several hours to a few days. Main symptoms include:
• Drooping eyelids
• Double vision
• Blurred vission
• Dry mouth
• Facial weakness on both sides of the face
• Paralysis
• Breathing trouble
• Vomiting, nausea and abdominal cramps
• Difficulty swallowing or speaking
Wound botulism:
The symptoms of wound botulism would be expressed more or less 10 days after the toxin has been absorbed by the body. Main symptoms include:
• Drooping eyelids
• Paralysis
• Facial weakness on both sides of the face
• Blurred vision
• Double vision
• Difficulty breathing
• Difficulty swallowing or speaking
There is a chance that the wound might not appear red and swollen.
Infant botulism:
Infant botulism is related to food (such as honey) and problems would usually begin within 18 to 36 hours after the toxin has been absorbed by the baby’s little body. Main symptoms include:
• Constipation (which is often the first sign)
• Weak cry
• Paralysis
• Drooping eyelids
• Irritability
• Floppy movements due to muscle weakness
• Trouble controlling the head
• Drooling from the mouth
• Tiredness
• Difficulty feeding or sucking

Foodborne botulism:
The source is generally from canned foods that have a low concentration of acid. This includes fruits, fish and vegetables. Scientists have also found that the disease can occur from chillies, oil infused with garlic and foil-wrapped baked potatoes.
Wound botulism:
When the botulinum bacteria gets into a person’s wound, it would multiply and then produce a certain toxin. Wound botulism has dramatically increased in the past years, especially with people who inject heroin. This is most likely due to the dirty needle that contains the spores of the botulinum bacteria.
Infant botulism
Infant botulism occurs after consumption of the bacterial spores. They would then grow and multiply in the intestinal tracts and as a result, produce toxins. The origin of infant botulism is believed to originate from honey, although it is most likely to be the exposure with contaminated soil.

Exposure to the botulinum toxin would occur through the following mechanisms: (note that the toxin cannot be absorbed through skin that is completely intact and healthy)
1. Ingesting the toxin.
2. Inhalation of the toxin.
3. Local production of the toxin (in the GIT).
4. Exposure caused by injection of the toxin.
5. Local production of toxin at devitalised tissue at a wound site.

The botulinum toxin would be activated through a process called “proteolytic cleavage”. The activated structure (of the toxin) contains 2 chains (heavy and light) and they are bound together by a single disulfide bond. It enters the blood stream and is then moved towards the neuromuscular junction. At the site of the neuromuscular junction, the heavy chain would bind to the peripheral synapse on the presynaptic side, on the neuronal membrane. The toxin would then enter the neuronal cell through a process called “receptor-mediated endocytosis”. The light chain would cross the membrane of the endocytic vesicle and then enter the cytoplasm. In the cytoplasm, the light chain would cleave some of the proteins that collectively form a complex called the synaptic fusion complex. This results in the inhibition of the release of acetylcholine. Now without the release of acetylcholine, action potentials cannot be propagated and muscles wouldn’t be able to contract. This lasts for about several months. The toxin doesn’t cross the blood brain barrier and as a result, the CNS remains intact.

The physical examination is commonly the first step in diagnosing botulism. Also common in diagnosing is; nerve conduction studies (EMG’s), brain scans and spinal fluid examinations are also helpful. The botulinum bacteria can also be isolated from the faeces of infected people that fall under the infant and foodborne branches of the disease.
There 2 ways to prevent foodborne botulism:
1. Prepare and store your food safely:
? Don’t eat the preserved food if it smells bad.
? Store oils that are infused with herbs or garlic in the fridge.
2. Can your food properly:
? Boil foods for about 10 min before eating them.
? Pressure-cook foods at 121 degrees Celsius for about 20-100 minutes depending on the food type.
Preventing infant botulism:
Avoid giving your child honey before the age of 1 (don’t even give them a tiny taste).

Preventing wound Botulism:
Never inject any type of drug unless it’s a medical practitioner doing so.

Foodborne botulism:
If the patient is diagnosed early, an antitoxin would be administered to inhibit the actions of the exotoxin. If the patient experiences respiratory failure, a mechanical ventilator as well as intensive care would be required.

Infant botulism:
Induce vomiting for the baby and insert enemas to remove or expel any contaminated food that was consumed. Supportive care is then required for your baby to recover properly.

Wound botulism:
Antitoxins would be administrated to neutralize and prevent the exotoxin from performing its actions. Another method for treating wound botulism is through surgical debridementand removal of the affected area, followed by supportive treatment.

3. C. Perfringens
People generally would experience symptoms between 6-24 hours after ingesting the toxin or bacteria. The toxins of this bacteria cause stomach cramps and abdominal pain that is followed by diarrhoea. Another common symptom is Nausea. Illness from the bacteria is rarely fatal and lasts up to around 24 hours.
The illness is caused by eating contaminated food that consists a large amount of the bacteria to produce enough toxins in the intestines to cause illness.
C. perfringens produces 4 main toxins (which are lethal), based on this, it is classified into 5 serological types. Based on this, they are classified from A to E. Additional virus factors also include, neuraminadase enterotoxin and haemolysins. The disease syndromes that are caused by the bacteria are from necrotizing enteritis, food poisoning and gas gangrene.

This bacteria produces neuronal and tissue destructive exotoxins that cause disease manifestations. The bacteria may become pathogenic when oxygen concentration and pH are low (Anaerobic environment). The disease can also occur after injecting drugs (street drugs).

Laboratories can diagnose the disease through identifying a type of toxin (produced by the bacteria) in the patient’s faeces or by determining the number of bacteria in the faeces. A count of 106 spores per gram of stool is needed to diagnose infection and also within 48 hours.
To prevent infection, one should follow these tips:
1. Cook meats thoroughly.
2. Store food in a fridge.
3. When heating cold food (coming from the fridge) make sure you heat it at a temperature of at least 74 degrees Celsius.
In severe cases doctors would prescribe intravenous fluids and electrolyte replacement to treat or prevent dehydration. In less severe cases, oral rehydration will suffice.
4. Other clostridial diseases Include:
1. Botulism (due to C. botulinum)
2. Clostridial necrotizing enteritis (due to C. perfringens type C)
3. Tetanus (due to C. tetani)
4. Gastroenteritis
5. C. difficile–induced colitis
6. Soft-tissue infections
7. Neutropenic enterocolitis (due to C. septicum)

5. Non-Spore forming anaerobes include:
Gram positive non-sporulating bacilli:
1. Bifidobacterium
2. Actinomyces
3. Arachnia
4. Proprionbacterium
5. Eubacterium
Gram negative non-sporulating bacilli (non-motile):
1. Fusobacterium
2. Bacteroides
3. Prevotella
4. Porphyromonas
Gram negative non-sporulating bacilli (motile):
1. Campylobacter
2. Treonema
3. Borrelia


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