Why it is so difficult to develop new antibiotics Over-reliance on and misuse of antibiotics has led to warnings of a future without effective medicines. Why is it so difficult for scientists to discover new drugs?
It's a tale of scientific discovery taught the world over: the serendipitous find of a mould that revolutionised modern medicine.
Almost 90 years ago, Alexander Fleming returned from holiday to find Penicillium on Petri dishes left in his basement laboratory at St Mary's Hospital in London.
By the 1950s, the golden age of antibiotic discovery, an array of new medicines was being found.
Today, scientists are searching for a new breakthrough, testing microbes in sources as diverse as soil, caves and Komodo dragon blood, as well as developing new, lab-made synthetic drugs. BBC News