Abstract
Penicillin permanently changed infectious disease research and therapeutic medicine, it transformed patient expectations and the structures of drug companies, contributed new insights in microbiology and molecular biology, and captured the public imagination and scientific breakthroughs. Alexander Fleming is the scientist who discovered an antibacterial activity in a Penicillium growth medium. To avoid repetition of the phrase “mold broth filtrate,” he coined the term “penicillin,” a substance that eventually became known as a “miracle drug.” Fleming's story has been told many times with enough elaboration that it is sometimes called the “Fleming myth.” This chapter elaborates Fleming's story which is quite fascinating. It is now known than penicillin controls bacteria by inhibiting their cell division. Hence, the phenomenon observed by Fleming—lysis—was extremely unusual. Penicillin was something new: a natural product of unknown structure with strong antibacterial activity. A major interdisciplinary effort was required to develop penicillin. Penicillin is the paradigm for natural products drug discovery; Fleming himself is an enduring role model not only for success in clinical research but also for how to project a positive popular image for the scientific profession.