Colony of penicillium

Penicillium is a common mould that you might find on bread and fruit, but it evolved to protect itself from infection by releasing chemicals that Alexander Fleming named penicillin. These chemicals disrupted the bacterial biology enough to kill off the bugs growing in the dish.

Once teams of researchers were able to capture and reproduce this chemical, it sparked a revolution in medicine, allowing people to fight infections that otherwise were untreatable. It also opened the door to many procedures that we consider to be a vital part of modern medicine, as we were suddenly able to protect patients from a variety of infections. Penicillin has allowed procedures such as hip and knee replacements, organ transplants, chemotherapy and protective care for premature babies, making medicine more effective.