Many different types of toxins are produced by microorganisms, like bacteria, which often aid them in their invasion of other organisms.


Necrotising fasciitis is a severe, life-threatening, flesh eating disease which infects the skin and can be caused by many types of bacteria. One of these is Staphylococcus aureus, and it is most commonly caused by the methicillin resistant strain (MRSA). The bacteria don't actually 'eat' the flesh as such, but release toxins that damage the tissues including streptococcal pyogenic exotoxins, which can also activate the immune system's T-cells and cause toxic shock syndrome (a severe side effect). Necrotising fasciitis can occur following any sort of trauma to the body, even minor ones such as a paper cut, when they come into contact with the bacteria.

Cyanobacteria (also known as blue-green algae) are a type of bacteria that can be found all over the world, in both the earth and the seas and oceans. They can most commonly be seen as 'blooms' that form in water, and look like algae – hence why they are sometimes known as blue-green algae. These blooms can form and spread very quickly, and can be dangerous to the other organisms that live in in the water, as they can sometimes produce cyanotoxins. These toxins can take lots of different forms and so can affect water-dwelling organisms in many different ways, as well as indirectly affecting and poisoning humans who may eat any of these marine creatures that have ingested the toxins, or by drinking the infected water. The affects these toxins have on humans vary according to the method of exposure, from vomiting to allergic reactions to liver damage.

Botulism is caused by neurotoxins produced by the Clostridium botulinum bacterium, and results in muscle paralysis. These toxins arise when foods such as beans are stored improperly, for example when foods have been home-stored and they don't have the correct storage conditions such as pH or pressure, and can be fatal to any who ingest them. The botulinum toxin is also used in the treatment known as 'Botox' – a very small amount of the toxin is injected into the skin to paralyse selected muscles. This can be used to treat both conditions such as trigerminal neuralgia (which causes facial pain) and for cosmetic work. Aside from this, the botulinum toxin is also a potential bioweapon threat: it would only take around 500g of the substance to kill half of the whole human population.

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Anthrax is an often lethal infectious disease caused by the bacteria Bacillus anthracis. It mostly affects the lungs, the gastrointestinal tract and the skin in humans. There are three possible ways to get an anthrax infection: cutaneously (through scrapes in the skin – the most common way), inhalation (spores are breathed in) or gastrointestinally (by eating infected meat). Once inside the body, the spores will germinate and release three proteins, which when combined can be lethal to humans. These proteins are what cause the symptoms of the disease (including tissue death and internal bleeding). Due to its ability to withstand harsh environmental conditions and its infectious nature (it can be spread around on clothes), anthrax has been used for bioterrorism in the past. For example, there was a case in the US in 2001 where anthrax infected letters were sent in the post, infecting 22 people and killing five.

Clostridium tetani is the bacterial cause of the disease tetanus, as it produces two potent toxins. The one that causes the symptoms of the disease is called tetanospasmin. This toxin is very similar to the botulinum toxin, but the effects are different. The effects of tetanospasmin include muscle spasms, which cause the skeletal muscles of the body to become rigid and can result in the failure of the respiratory system. However, there is a method of prevention for this disease in the form of a vaccine, which has greatly improved infection rates around the world since it started to be used widely.

What strain of S. aureus most commonly causes necrotising fasciitis?
Methicillin resistant staphylococcus aureus (MRSA) is the strain of S. aureus which most frequently causes necrotising fasciitis.
What do Cyanobacteria form when they multiply in water?
Cyanobacteria form blooms when they reproduce in water.
How much botulinum toxin is required to kill half the human population of the world?
500g of botulinum toxin would be enough to kill half the entire human population.
What bacteria causes the disease known as Anthrax?
Bacillus anthracis is the bacteria which causes Anthrax.
What toxin secreted by Clostridium tetani causes the symptoms of the disease tetanus?
Tetanospasmin is the toxin which causes the symptoms of tetanus.