History of antibiotics: Who first observed and reported the antibiotic and therapeutic properties of penicillin?

Introduction / Context:
Understanding who first recognized penicillin’s antibacterial action is foundational to the history of antibiotics. Penicillin opened the modern era of antimicrobial chemotherapy and transformed clinical medicine.

Given Data / Assumptions:

• The question asks for the first observation and report of penicillin’s antibiotic properties.
• We distinguish discovery/observation from later isolation, purification, and development.

Concept / Approach:
In 1928, Alexander Fleming noticed that a Penicillium mold contaminant inhibited Staphylococcus bacterial growth on an agar plate. He described the antibacterial substance “penicillin” and its therapeutic potential, though large-scale production and clinical deployment came later through the work of Florey, Chain, and colleagues.

Step-by-Step Solution:

Verification / Alternative check:
Standard medical histories credit Fleming with the initial observation; Nobel Prize in 1945 was awarded to Fleming, Florey, and Chain for penicillin.

Why Other Options Are Wrong:

• E. P. Abraham: helped elucidate penicillin chemistry but was not the first observer.
• Louis Pasteur: pioneered germ theory, vaccines, and fermentation science, not penicillin.
• S. C. Prescott: known for food science and microbiology texts, not penicillin’s discovery.

Common Pitfalls:
Confusing discovery (Fleming) with development (Florey & Chain) or later chemical characterization.

Final Answer:
Alexander Fleming