Four years ago professor Sally Davies, England's chief medical officer, gave the world a sombre warning of the growing threat posed by bacteria evolving resistance to life-saving antibiotics. If this were left unaddressed, she argued, it would lead to the erosion of modern medicine as we know it. Doctors and scientists had long warned of the problem, but few outside medicine were taking real heed. Consumption of antibiotics rose 36% between 2000 and 2010, writes Ed Whiting, director of policy and chief of staff at Wellcome, a biomedical research charity based in London. He notes that much of the progress in the field is yet to be made: We urgently need new antibiotics. No new classes of antibiotics have been approved since the early 1980s. Between 1940 and 1962 about 20 classes were produced, but industry backing has decreased significantly since that golden age. The pipeline of new treatments is all but dry, the void fast exploited by resistant bacteria. A concerning number are now resistant to drugs reserved as the last line of defence, and the most vulnerable are in greatest danger -- the young, old and critically ill. Blood infections caused by drug-resistant microbes kill more than 200,000 newborn babies each year. The reason for the lack of interest from the pharmaceutical industry is simple: the economics don't add up. Developing new antibiotics is scientifically challenging, time-consuming and costly. The medicines we so badly need cannot be allowed to be sold in volume; they must be conserved for real need, with fair access guaranteed. This limits their retail value. Many early-stage projects will fail, making them a risky bet. Even those that are successful will take at least a decade to produce medicines that are safe for human use.