Scientists have pinpointed a promising new source of antibiotics: ants. They have found that some species – including leaf-cutter ants from the Amazon – use bacteria to defend their nests against invading fungi and microbes.

Chemicals excreted by the bacteria as part of this fight have been shown to have particularly powerful antibiotic effects and researchers are now preparing to test them in animals to determine their potential as medicines for humans.

Doctors say new antibiotics are urgently needed as superbug resistance to standard antimicrobial agents spreads. More than 700,000 people globally now die of drug-resistant infections each year, it is estimated – and some health officials say this figure could be even higher.