New diagnostic tests are urgently needed to curb the over-use of antibiotics, according to a report from superbug tsar Jim O'Neill.
The economist set out plans to spur on the development and use of diagnostic procedures over the next five years.
Such tests could be used by GPs and other health professionals to avoid confusion over when antibiotics should be prescribed.
A study cited in the report found that two thirds of courses of antibiotics were likely to have been inappropriately prescribed for infections caused by viruses or conditions not linked to infection at all.
While bacteria respond to the drugs, viruses do not. Excessive use of antibiotics, partly due to the wrong patients receiving them, is one of the main driving forces of microbial resistance.
Lord O'Neill, brought in by the Government to chair the Review on AMR (antimicrobial resistance), said: "For far too long we haven't recognised the huge cost to society of increasing resistance when we use antibiotics that we don't need - such as antibiotics for flu which have no effect except to increase the chances of superbugs developing.
"To avoid the tragedy of 10 million people dying every year by 2050, the world needs rapid diagnostics to improve our use of antibiotics. They are essential to get patients the right treatment, cut down on the huge amount of unnecessary use, and make our drugs last for longer."
His report, the latest in a series on tackling the superbug threat, proposed subsidies for developers of new tests paid from a proposed international fund set up to promote antibiotic development.
Other suggestions included moving more cash into early stage research to jump-start innovation, and building the long-term economic case for rapid diagnostics.
Dame Sally Davies, chief medical officer for England, said: "As this report from Lord O'Neill clearly sets out, rapid diagnostics have a pivotal role to play in the fight against drug resistant bacteria.
"Without them, it is much harder for prescribers to know with any certainty whether an antibiotic will treat the infection. We need co-ordinated international action to help spur innovation and improve antibiotic use before it is too late."
Dr Des Walsh, head of infections and immunity at the Medical Research Council (MRC), said: "In England, nine out of 10 GPs say they feel pressured to prescribe antibiotics, and we know a quarter of the 41.6 million antibiotic prescriptions issued a year are given unnecessarily for illnesses like colds or ear infections caused by viruses. It's not rocket science to see that our doctors, already doing a fantastic job under huge amounts of pressure, need the right tools to diagnose properly.
"Part of the problem is that it's cheaper and quicker to prescribe an antibiotic, 'just in case' it's effective. We need to be able to tell accurately whether an illness is due to a bacterial infection and if so which antibiotic to use, or we risk losing a raft of drugs that are crucial to prevent infections after serious operations like caesareans, transplants or to treat illnesses like pneumonia or kidney infections."