ALEXANDER FLEMING & DISCOVERY OF PENICILLIN

Alexander Fleming (1881-1955) was studying the bacterium Staphylococcus that causes throat infection.he was growing this organism in petri plates on agar medium.it is a common observation that such culture media often get contaminated with other microbes.fleming observed contamination of a blue -green mould Penicillium notatum, in one of his culture plates.normally contaminated cultures are discarded but fleming retained this particular plate.it looked different ,as the normal cloudy aqearance resulting from bacterial growth was absent.the presence of a clear area round the mould indicated that bacterial growth had been inhibited.many other bacteriologists had also made the observation that moulds inhibit bacterial growth.but fleming wanted to know why.further investigation led to the discovery that toxic substance produced by the mould inhibited bacterial growth.fleming named this substance penicillin (1928-29).he made the cautious statement that penicillin might prove to be an effective antiseptic agent against  penicilin sensitive microbes.subsequently tests showed that penicillin was not toxic to human beings and thus it became one of the most useful antibiotics.during world war 2, penicillin proved to be of tremendous value in controlling infections among wounded soldiers.

by: ashwani kumar @Vigyan Tutorials ,patel nagar. opp anoop hospital, phagwara