Penicillin 1928 – A Revolution in the Fight Against Bacterial Diseases

Scottish biologist Alexander Fleming later recalled his thoughts about his discovery:

 “When I woke before dawn on the morning of 28 September 1928, I had not planned to revolutionise all of medicine by discovering the world's first antibiotic or bacteria-killer. But I suppose that is exactly what I did.” 

When Fleming returned from a holiday, he noticed mould in a contaminated Petri dish containing Staphylococcus bacteria. He also noticed that bacterial growth was inhibited near the mould. He therefore concluded that the mould secreted a substance that suppressed bacterial growth. He soon grew a pure mould culture in a growth medium. Identifying the mould as belonging to the genus Penicillium, he named the antibiotic substance in the medium penicillin. 

Interestingly, many ancient societies had noted that mould could be used as a remedy. Irish physicist John Tyndall demonstrated the antibacterial effect of the Penicillium fungus in 1875. However, Fleming was the first to suggest that this mould secreted an antibacterial substance and later to isolate it. Subsequent studies showed that penicillin works by weakening bacterial cell walls.

In 1941, Australian pharmacologist Howard Florey, German biochemist Ernst Chain and British biochemist Norman Heatley, working together in England, succeeded in turning penicillin into a usable drug. They showed that the drug could treat infections in mice and humans. 

The US and British governments decided to produce as much penicillin as possible to help their soldiers during World War II. Penicillin soon came to be used to treat major bacterial diseases:

• Blood poisoning
• Pneumonia
• Diphtheria
• Scarlet fever
• Gonorrhoea 
• Syphilis

Unfortunately, antibiotic-resistant bacteria evolved, requiring the search for additional antibiotics. Moulds are not the only natural source of antibiotics. For example, Streptomyces bacteria were a source of streptomycin and tetracyclines. Penicillin and these subsequently discovered antibiotics launched a revolution in the fight against bacterial diseases.

Description of the article image: A close-up view of the Penicillium fungus

Historical figures mentioned in the article: John Tyndall (1820–1893), Alexander Fleming (1881–1955), Howard Walter Florey (1898–1968), Ernst Boris Chain (1906– 1979), Norman George Heatley (1911–2004)

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