The Origin of Penicillin

The history of the application of molds as treatment for wounds and infection can be traced far back to ancient Egypt, India and Greece. Warm soil, wet bread mixed with spider webs (containing spores) were techniques by which the healing properties of molds were utilized. Its use as a form of treatment was first recorded by apothecaries around 1640 in England.

The discovery of penicillin ushered in a new age of antibiotics derived from microorganisms. Penicillin is an antibiotic the mold thrives in a liquid culture containing a mixture of sugar and other nutrients as well as a source of nitrogen. As the mold grows, it exhausts the sugar and only begins producing penicillin after using up most of the nutrients for growth.

All penicillins work in the same way; 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.

Penicillin was discovered in 1928 by Dr Alexander Fleming when his assistant accidentally left the window to his laboratory open overnight and by morning, mold spores had covered his staphylococcus bacterial specimens in a petri dish. Upon examination, he noticed that colonies of the staphylococcus bacteria that were contaminated by the mold were either dead or dying (which was later discovered to be as due to the mold’s prevention of the bacteria from making new cell walls.

However, this species of the Penicillium fungi identified as Penicillium notatum (but later discovered to be Penicillium rubens had a major drawback; the difficulty in production and dilution which meant that this specie of penicillium could not produce enough commercial quantities of penicillin. Concerted efforts were made to discover strains of the penicillium which produces a higher yield of penicillin. These efforts were successful, leading to the discovery of the fungus Penicillium chrysogenum was discovered, on a cantaloupe from a grocery store in Peoria, Illinois. Penicillium chrysogenum was found to produce a yield of penicillin several hundred times as much as Fleming’s original cultures. Subcultures of this fungus were then irradiated with X-rays and UV rays in an attempt to cause a mutation in the fungus that would lead to an increase in penicillin yield. The efforts led to the creation of a mutant strain of penicillium chrysogenum that yielded a thousand times more penicillin as Fleming’s original culture was produced and cultured.

The discovery of ways of mass producing penicillin was instrumental in preventing death from infection during the Second World War.

In the war, penicillin was instrumental in the reduction of death tolls. Before its discovery, the major killers in wars have been infection rather than battle injuries with death numbers resulting from bacterial infections dropping dramatically. By the end of the Second World War, American Pharmaceutical companies were producing over 600 billion units of penicillin a month.

Penicillin is used in the treatment infections, including throat infections, syphilis, meningitis and other infections. The most common side effects of penicillin are hypersensitivity reactions which include skin rash, hives, swelling and anaphylaxis. More serious side effects are not common.