Microbiology Practice Exam 2025 – Complete Study Resource

The discovery of penicillin is credited to Alexander Fleming, who made this significant breakthrough in 1928. Fleming, a Scottish bacteriologist, observed that a mold called Penicillium notatum produced a substance that killed a wide variety of bacteria. This observation arose from his experimentation with Staphylococcus bacteria; when he returned from vacation and noticed that his bacterial cultures had been contaminated by mold, he discovered that the bacteria surrounding the mold were being destroyed.

This accidental discovery laid the groundwork for the development of penicillin as the first true antibiotic, which has had a profound impact on medicine and the treatment of bacterial infections. Fleming's work highlighted the importance of naturally occurring molecules in fighting infections, leading to the therapeutic use of antibiotics that we rely on today. Fleming's contribution fundamentally changed the landscape of medicine and microbiology.