What type of scientist was Alexander Fleming besides a physician?

Besides being a physician, Alexander Fleming was a microbiologist.

Microbiology is the study of microscopic organisms, including bacteria and fungi. Fleming’s medical training and laboratory work made the field a natural focus: he investigated how infections developed and how substances might destroy harmful bacteria without damaging human tissue.

His best-known discovery came in 1928, when he noticed that a mould contaminating a culture plate inhibited nearby staphylococcal bacteria. He named the antibacterial substance penicillin. Fleming had earlier discovered lysozyme, an enzyme with antibacterial properties, in 1922.

A common mix-up is to call Fleming simply a “chemist” or the sole inventor of modern penicillin treatment. He was a physician and microbiologist who identified penicillin’s potential; Howard Florey, Ernst Chain and their colleagues later developed methods that made the drug usable on a large scale.