Sir Alexander Fleming

Background
When Sir Alexander Fleming,  as an army surgeon, was treating a large number of soldiers who got injured, he noticed that antiseptic solution was not useful.
In the First World War, the wounded had festering wounds, and with the medicine of that time no one able to cure them.
Therefore, he began to research disinfectant material.
He cultured many bacteria and repeated an experiment ?many experiments? I am not sure what you mean.
One day, tidying his messy room, he found that green mold had spread on the medium which cultured bacteria.
It happened by mistake. He had left the cover off the bottle of the medium.
At that time, he noticed that bacteria disappeared around the green mold.
He thought that the green mold may have an ingredient which had killed the bacteria.

Research Question
Does the green mold sterilize bacteria?

Methods and Data
In 1928, Fleming found that green mold killed bacteria. He diluted a filtrate of the mold because he was not able to isolate penicillin.
In 1928, he found that applying penicillin was effective for treatment.
In 1940, H.W.Florey and E.B.Chain succeeded in isolating penicillin. In addition, they gave penicillin to a mouse which had been infected with a staphylococcus, and succeeded in the treatment of the mouse.
In 1941, they gave penicillin to a patient who was infected with bacteria and seriously wounded, and the effect was confirmed.

Conclusions
Penicillin was one of the medicines that saved the most lives.
However, the war against bacteria hadn't finished.
New bacteria, resistant bacteria, appeared. They were tolerant of antibiotics.
Bacteria evolve and get resistant to antibiotics whenever people produce new antibiotics.
The war against bacteria will continue in the future.