In 1928, microbiologist Alexander Fleming noticed something peculiar while examining the petri dishes used to grow bacteria in his laboratory. Amongst the small, circular bacterial colonies growing on the plate was a contaminating mold. He noticed that the bacterial colonies closest to the mold were dying, yet those that were far from the mold seemed healthy. Fleming theorized that the mold (later identified as Penicillium) was producing a substance lethal to the bacteria — an antibiotic.
Fleming’s hypothesis turned out to be correct, and within a decade, the antibiotic we know as penicillin was born. Upon accepting the Nobel Prize in 1945, Fleming left us with a prescient premonition that was largely ignored: “The thoughtless person playing with penicillin treatment is morally responsible for the death of the man who succumbs to infection with the penicillin-resistant organism. I hope this evil can be averted.”