Bacterial defences of fungus-farming ants could help in medical battle against superbugs
Robin McKie Science editor
Saturday 24 September 2016 12.17 BST Last modified on Saturday 24 September 2016 22.00 BST
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.
Last week, UN secretary general Ban Ki-moon, speaking at the first general assembly meeting on drug-resistant bacteria, said antimicrobial resistance was now a fundamental threat to global health.
This was reiterated by Professor Cameron Currie of the University of Wisconsin–Madison, one of the scientists involved in the ant research.
“Antibiotic resistance is a growing problem,” he said last week. “However, pinpointing new antibiotics using the standard technique of sampling soil for bacteria is tricky. On average, only one in a million strains proves promising. By contrast, we have uncovered a promising strain of bacteria for every 15 strains we have sampled from an ant’s nest.”
Only a very specific group of ants are proving useful in this work, however. These are species that farm fungi in tropical regions in North and South America.
“These ants forage for plant material, which they bring back to their nests and feed to a fungus,” said Professor Jon Clardy of Harvard Medical School. “The fungus breaks down the plant material and the ants feed on the fungus.”