The history of penicillin follows a number of observations and discoveries of apparent evidence of antibiotic activity in molds before the modern isolation of the chemical penicillin in 1928.

There are anecdotes about ancient societies using molds to treat infections, and in the following centuries, many people observed the inhibition of bacterial growth by various molds.

However, it is unknown if the species involved were Penicillium species or if the antimicrobial substances produced were penicillin.

The Scottish physician Alexander Fleming was the first to suggest that a Penicillium mold must secrete an antibacterial substance and the first to concentrate the active substance involved, which he named penicillin, in 1928.

Penicillin was the first modern antibiotic. During the next twelve years, Fleming grew, distributed, and studied the original mold, which was determined to be a rare variant of Penicillium notatum (now Penicillium chrysogenum).

Many later scientists were involved in the stabilization and mass production of penicillin and in the search for more productive strains of Penicillium.

Important contributors include Ernst Chain, Howard Florey, Norman Heatley, and Edward Abraham. Shortly after the discovery of penicillin, scientists found that some disease-causing pathogens display antibiotic resistance to penicillin.

Research that aims to develop more effective strains and to study the causes and mechanisms of antibiotic resistance continues today.

Early history

Many ancient cultures, including those in Egypt, Greece, and India, independently discovered the useful properties of fungi and plants in treating the infection.

These treatments often worked because many organisms, including many species of mold, naturally produce antibiotic substances. However, ancient practitioners could not precisely identify or isolate the active components of these organisms.

In Sri Lanka in the second century BC, soldiers in the army of king Dutugemunu (161–137 BC) are recorded to have stored oil cakes (a traditional Sri Lankan sweetmeat) for long periods in their hearth lofts before embarking on military campaigns in order to make a poultice of the cakes to treat wounds.

In 17th-century Poland, wet bread was mixed with spider webs (which often contained fungal spores) to treat wounds.

The technique was mentioned by Henryk Sienkiewicz in his 1884 book With Fire and Sword. In England in 1640, the idea of using mold as a form of medical treatment was recorded by apothecaries such as John Parkinson, King’s Herbarian, who advocated the use of a mold in his book on pharmacology.

Early scientific evidence

The modern history of penicillin research begins in earnest in the 1870s, in the United Kingdom. Sir John Scott Burdon-Sanderson, who started out at St. Mary’s Hospital (1852–1858) and later worked there as a lecturer (1854–1862), observed that culture fluid covered with mold would produce no bacterial growth.

Burdon-Sanderson’s discovery prompted Joseph Lister, an English surgeon and the father of modern antisepsis, to discover in 1871 that urine samples contaminated with mold also did not permit the growth of bacteria.

Lister also described the antibacterial action on human tissue of a species of mold he called Penicillium glaucum.

A nurse at King’s College Hospital whose wounds did not respond to any traditional antiseptic was then given another substance that cured her, and Lister’s registrar informed her that it was called Penicillium.

In 1874, the Welsh physician William Roberts, who later coined the term “enzyme“, observed that bacterial contamination is generally absent in laboratory cultures of Penicillium glaucum.

John Tyndall followed up on Burdon-Sanderson’s work and demonstrated to the Royal Society in 1875 the antibacterial action of the Penicillium fungus.

By this time, Bacillus anthracis had been shown to cause anthrax, the first demonstration that a specific bacterium caused a specific disease.

In 1877, French biologists Louis Pasteur and Jules Francois Joubert observed that cultures of the anthrax bacilli, when contaminated with molds, could be successfully inhibited.

Some references say that Pasteur identified the strain as Penicillium notatum. However, Paul de Kruif’s 1926 Microbe Hunters describes this incident as contamination by other bacteria rather than by mold. In 1887, Garré found similar results.

In 1895, Vincenzo Tiberio, an Italian physician at the University of Naples, published research about mold in a water well in Arzano that showed antibacterial action.

Two years later, Ernest Duchesne at École du Service de Santé Militaire in Lyon independently discovered the healing properties of a Penicillium glaucum mold, even curing infected guinea pigs of typhoid.

He published a dissertation in 1897 but it was ignored by the Institut Pasteur. Duchesne was himself using a discovery made earlier by Arab stable boys, who used molds to cure sores on horses.

He did not claim that the mold contained any antibacterial substance, only that the mold somehow protected the animals. The penicillin isolated by Fleming does not cure typhoid and so it remains unknown which substance might have responsible for Duchesne’s cure.

In Belgium in 1920, Andre Gratia and Sara Dath observed fungal contamination in one of their Staphylococcus aureus cultures that was inhibiting the growth of the bacterium.

They identified the fungus as a species of Penicillium and presented their observations as a paper, but it received little attention.

An Institut Pasteur scientist, Costa Rican Clodomiro Picado Twight, similarly recorded the antibiotic effect of Penicillium in 1923.

Modern breakthroughs

In 1928, Scottish biologist Alexander Fleming noticed a halo of inhibition of bacterial growth around a contaminant blue-green mold on a Staphylococcus plate culture.

He concluded that the mold was releasing a substance that was inhibiting bacterial growth. He grew a pure culture of the mold and subsequently concentrated what he later named “penicillin“.

During the next twelve years, Fleming grew and distributed the original mold, which was eventually identified as Penicillium notatum. He was unsuccessful in making a stable form of it for mass production.

Cecil George Paine, a pathologist at the Royal Infirmary in Sheffield, attempted to treat sycosis (eruptions in beard follicles) with penicillin but was unsuccessful, probably because the drug did not penetrate deep enough.

Moving on to ophthalmia neonatorum, a gonococcal infection in babies, he achieved the first cure on 25 November 1930. He cured four patients (one adult, the other infants) of eye infections, although a fifth patient was not so lucky.


*This article was originally published at