What are they?
Antibiotics are chemical substances produced by bacteria or fungi that kill or prevent the growth of another species of micro-organism.
Types
The first type of antibiotic we will look at are bacteriocidal. This means they kill bacteria. Penicillin is an example of this type.
The second type are bacteriostatic antibiotics, these inhibit the growth of bacteria; allowing the natural defenses of the body to catch up with production of antibodies. An example is chloramphericol.
Penicillin
This was the first antibiotic to be discovered (1928). A research team led by Ernst Chain and Howard Florey worked to develop it as a drug and by 1941 it was being produced on a reasonably large scale.
The chemical is produced by the fungus Penicillium Notatum and works by preventing the manufacture of a cell wall in a number of bacteria. This means the cell will keep taking on water by Osmosis and eventually burst (lysis) as it has no way of support.
Penicillin is produced by fermentation
Limitations
Antibiotics are useless against viruses because they do not perform any of the functions that antibiotics stop: it is not possible to kill something that isn't living in the first place!
For this reason, taking antibiotics when you have a cold, flu or even hepatitis will do nothing to cure you, and will do more harm than anything else by attacking the 'good bacteria' your body needs to survive.
Over use of antibiotics can lead to bacteria becoming resistant to them. By natural selection, bacteria will mutate and evolve to more resistant strains. Health experts fear this could lead to all antibiotics being useless in a short space of time. Making treatment for infections much more serious, as it was before antibiotics were discovered.
MRSA stands for methicillin resistant staphylococcus aureus [meth - e - si - lin] resistant [straf - e - lo - cok - us] [or - e - us]. Methicillin is an antibiotic developed in the late 1950s, that was effective at killing straphylococcus aureus - which was resistant to almost every antibiotic.
MRSA occurs on the skin and especially nostrils, harmlessly. But when it enters the body, like through an open wound during surgery, it can be fatal.