The discovery of penicillin, one of the world’s first antibiotics, marks a true turning point in human history — when doctors finally had a tool that could completely cure their patients of deadly infectious diseases. Many school children can recite the basics. Penicillin was discovered in London in September of 1928.As the story goes, Dr. Alexander Fleming, the bacteriologist on duty at St. Mary’s Hospital, returned from a summer vacation in Scotland to find a messy lab bench and a good deal more.he discovery of penicillin, one of the world’s first antibiotics, marks a true turning point in human history — when doctors finally had a tool that could completely cure their patients of deadly infectious diseases. Many school children can recite the basics. Penicillin was discovered in London in September of 1928.