Alexander Fleming, who is credited with discovering penicillin in Sample of penicillium mould presented by Alexander Fleming to Douglas Macleod, Starting in the late 19th century there had been many accounts by scientists and physicians on the antibacterial properties of the different types of moulds including the mould penicillium but they were unable to discern what process was causing the effect. Fleming concluded that the mould released a substance that repressed the growth and caused lysing of the bacteria. Fleming coined the term "penicillin" to describe the filtrate of a broth culture of the Penicillium mould.
The several kinds of penicillin synthesized by various species of the mold Penicillium may be divided into two classes: Because it is possible to change the characteristics of the antibiotic, different types of penicillin are produced for different therapeutic purposes.
Because of its poor stability in acid, much of penicillin G is broken down as it passes through the stomach ; as a result of this characteristic, it must be given by intramuscular injection, which limits its usefulness.
Penicillin V, on the other hand, typically is given orally; it is more resistant to digestive acids than penicillin G. Some of the semisynthetic penicillins are also more acid-stable and thus may be given as oral medication. All penicillins work in the same way—namely, by inhibiting the bacterial enzymes responsible for cell wall synthesis in replicating microorganisms and by activating other enzymes to break down the protective wall of the microorganism.
As a result, they are effective only against microorganisms that are actively replicating and producing cell walls; they also therefore do not harm human cells which fundamentally lack cell walls.
This has led to the production of the penicillinase-resistant penicillins second-generation penicillins. Moreover, some strains of Staphylococcus have become resistant to penicillinase-resistant penicillins; an example is methicillin-resistant Staphylococcus aureus MRSA.
Penicillins are used in the treatment of throat infections, meningitissyphilisand various other infections. The chief side effects of penicillin are hypersensitivity reactions, including skin rash, hivesswelling, and anaphylaxisor allergic shock.
The more serious reactions are uncommon.
Milder symptoms may be treated with corticosteroids but usually are prevented by switching to alternative antibiotics. Anaphylactic shock, which can occur in previously sensitized individuals within seconds or minutes, may require immediate administration of epinephrine.History powerpoint presentations free to download.
Powerpoint presentations on a huge range of history topics.
Ideal for use in the classroom, student learning or general knowledge. Great for KS1 KS2 KS3 KS4 and post 16 A level lessonplans, and more.
Great site for KS1, KS2, KS3, KS4, A level, K Miller’s doctor used that connection to get the government—which had tight control over key medicines during wartime—to release roughly a tablespoon of penicillin for his patient.
Drugs in the penicillin class work by indirectly bursting bacterial cell walls.
They do this by acting directly on peptidoglycans, which play an essential structural role in bacterial cells. The historical record suggests otherwise, but penicillin did bring Fleming election to the Royal Society (), a knighthood (), and a share, with Florey and Chain, of the first post-war Nobel Prize in Physiology or Medicine in Time Traveler for penicillin.
The first known use of penicillin was in See more words from the same year. This is an excellent history of the long road to the use of penicillin for treating infectious diseases. The book provides interesting background about Fleming, his family, his career, and his personality that impacted his discovery of penicillin and influenced his attempts to isolate the drug in sufficient quantities for animal and clinical testing.