Who discovered that penicillin could kill some bacteria?

The discovery of penicillin's antibacterial properties is attributed to Alexander Fleming. In 1928, while working at St. Mary's Hospital in London, Fleming observed that a mold called Penicillium notatum had contaminated his Petri dishes and was inhibiting the growth of Staphylococcus bacteria. This fortuitous finding led to the realization that the mold was producing a substance capable of killing bacteria, which he named penicillin.

Fleming's work laid the foundation for the development of antibiotic treatments, which revolutionized medicine. His discovery highlighted the potential of naturally occurring compounds in fighting bacterial infections, ultimately saving countless lives.

The other individuals mentioned—Watson and Crick, who are known for their work on the structure of DNA, and Banting and Best, who discovered insulin—were significant figures in their own fields but were not involved in the discovery of penicillin. Fleming's serendipitous observation and subsequent research led to a breakthrough in pharmacology that directly addressed bacterial infections.