Antibiotics
Antibiotics are natural substances that can be used to fight bacterial infections. They are produced and secreted naturally by bacteria and fungi. Biotechnology is used to produce them in forms and quantities that allow safe administration to people suffering from bacterial infections.
The first antibiotic discovered was penicillin. Penicillin was first widely used on large numbers of patients in World War II (1939–45), after being discovered in 1928 by Scottish scientist Alexander Fleming. Howard Florey (from Australia) and Ernst Chain (originally from Germany) later discovered how to collect and purify penicillin from the fungus that produces it.
Bacteria can be gram-positive, with thick cell walls made of peptidoglycan. Examples include Staphylococcus aureus (which causes mastitis in cows) and Streptococcus cremoris, a bacterium used in dairy production. Bacteria can also be gram-negative, with a cell wall high in lipid content and low in peptidoglycan content. Examples include the Yersinia pestis bacterium that is thought to have caused the Black Plague and most bacteria that cause bowel-related illnesses such as Salmonella food poisoning.
A few antibiotics used to fight infections include:
- Erythromycin – obtained from Streptomyces erythreus and effective against many gram-positive bacteria and some gram-negative bacteria.
- Ampicillin – a semisynthetic penicillin which acts against more bacteria than penicillin. It is effective against gram-negative and gram-positive bacteria and used to treat gonorrhoea and infections of the intestinal, urinary, and respiratory tracts.
- Novobiocin - produced by Streptomyces nivens and used to treat infections by gram-positive bacteria.
Natural antibiotics - work sheet [PDF 59kb | 2 pages]
Read more on the discovery of penicillin and play the game: http://nobelprize.org/medicine/educational/penicillin/index.htm