More than 80 international drug and biotechnology companies have urged governments to work with them to combat the emergence of drug-resistant superbugs, according to a report by news agency Reuters.

In a declaration at the World Economic Forum in Davos, Switzerland, the companies called for coordinated efforts to cut unnecessary use of antibiotics and support the development of new ones.

Superbugs could kill tens of millions of people within decades unless new antibiotics are found, they said. The problem has risen in importance in recent years as many common infections are not responding to conventional drugs and drug companies have cut back on investment in this field.

The discovery of a gene called mcr-1 in China that makes bacteria resistant to all known antibiotics has also rung alarm bells.

Andrew Witty, CEO of GlaxoSmithKline (GSK), said the difficulty of finding new antibiotics was highlighted by the fact that mass screenings of hundreds of millions of chemicals at GSK and two other large firms over nine years had yielded no potential new drugs. This, he said, was because it is an extremely difficult area to make progress in.

Companies that have signed the Davos declaration include Merck, Pfizer, Sanofi, Novartis and AstraZeneca, among others.

In the pact, they pledged to encourage more appropriate use of antibiotics, including reduced use in livestock, better education of doctors and nurses, and improved infection control.

They also urged more affordable access to antibiotics all over the world and better collaboration between researchers at drug companies and those at universities and governments.