Promising new antibiotic discovered in worm gut microbiome

We’re currently in dire need of new weapons against infectious bacteria, especially those in a tough-to-kill class known as gram-negative bacteria. Now, researchers at Northeastern University have discovered just that, hiding in the gut of a tiny, soil-dwelling, parasitic worm. Tests on mice have so far proved promising.

The new antibiotic, dubbed darobactin, was discovered in the gut microbiome of nematodes. These tiny worms are parasites that live inside the digestive systems of caterpillars and other insects. Once there, they release a bacteria called Photorhabdus, which kill the caterpillar so that both the worm and bacteria can feast on it.

And in order to prevent other opportunistic microbes from stealing the meal, the Photorhabdus produce an antibiotic compound. And this was the basis for darobactin.

Importantly, the new compound can kill gram-negative bacteria, a notoriously hardy class of bugs that have a second membrane in their cell walls. The researchers found that darobactin binds to a protein called BamA, jamming the mechanism that the bug uses to build its cell wall and killing them.

The researchers tested the drug against gram-negative bacteria both in the lab and in mice, and found it to be effective. And while there’s always the chance that bacteria will eventually develop resistances to any new drugs, the team noticed an interesting twist. Bugs that evolved resistance to darobactin lost the ability to infect mice. The BamA protein appears to be too important for the bacteria to change, and hopefully that should mean the drug remains unresisted for longer.