Penicillins: Discovery, History, and Clinical Use

Antibiotics in the Penicillin Group

β-lactam Antibiotics: Discovery, History, and Clinical Use

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• What are Penicillins?
• Discovery by Alexander Fleming
• Development at Oxford
• Clinical Use and Natural Penicillins
• Allergies and Tolerance
• Semisynthetic Penicillins
• Conclusion

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1

What are Penicillins?

β-lactam antibiotics from Penicillium moulds

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• Group of β-lactam antibiotics originally from Penicillium moulds (P. chrysogenum, P. rubens)
• Most in clinical use synthesised via deep tank fermentation and purified
• Natural penicillins: Penicillin G (IM/IV), Penicillin V (oral)
• Effective against staphylococci and streptococci bacterial infections
• Many bacteria developed resistance due to extensive use

• 10%: Population claims allergy
• 90%: Can tolerate penicillin
• 3%: Cross-reactivity

2

Discovery and History

From 1928 observation to Nobel Prize and WWII production

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1928: Fleming's Discovery Alexander Fleming identifies antibacterial substance from Penicillium rubens mould at St Mary's Hospital 1930: First Clinical Use Cecil George Paine treats neonatal conjunctivitis 1939-1940: Oxford Team Purifies Florey, Chain et al. develop cultivation, extraction, and purification methods 1942: Treats Meningitis Fleming uses purified penicillin for streptococcal meningitis 1945: Nobel Prize Fleming, Florey, Chain awarded Nobel in Physiology or Medicine WWII: Mass Production US and Allies produce penicillin, saving thousands of soldiers' lives

> The discovery of penicillin was one of the most important scientific discoveries in the history of medicine.

— Wikipedia Summary

• Scottish physician, 1881-1955
• Discovered penicillin in 1928 at St Mary's Hospital, London
• Observed Penicillium mould inhibiting staphylococci
• Shared 1945 Nobel Prize with Florey and Chain

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3

Semisynthetic Penicillins

Broader spectrum against resistant bacteria

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• Developed for broader spectrum: antistaphylococcal, aminopenicillins, antipseudomonal
• More potent and effective against wider range of bacteria
• Penicillin resistance reported shortly after discovery
• Ongoing research into resistance mechanisms
• Agriculture uses: added to feed for growth promotion and disease control

Penicillins: Revolutionized antibiotic treatment since 1928 From natural mould extracts to semisynthetic powerhouses Overcoming allergies and resistance challenges

Thank you for your attention! Questions?

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