The discovery of a virus, that kills ‘sleeping’ bacteria, may be another key player in the fight against antibiotic resistance, a Swiss study has found.

The research, at ETH Zurich and the University of Basel, found a type of bacteria-killing virus, called a bacteriophage, in rotting plant material.

Bacteriophage are emerging as a promising alternative to antibiotics in combating antibiotic-resistant infections, but this so-called phage therapy has so far not been effective in dormant bacteria – which ‘shut down’ their life processes to survive harsh environmental conditions. This is because the phages cannot penetrate the bacteria in this state.

However the new phage (pictured), named Paride by the scientists, is able to kill a bacteria called Pseudomonas aeruginosa in its dormant state. The species is found in the environment as well as the body, where it can cause potentially fatal pneumonia.

On its own, Paride killed 99% of dormant bacteria when tested on cell cultures in the lab. And when combined with an antibiotic, which usually has no effect on these bacteria, it could eradicate the bacteria completely – this also proved to be the case when tested in mice with chronic infections.

First author Enea Maffei said: “This shows that our discovery is not just a laboratory artefact, but could also be clinically relevant.”

It is still not clear how Paride works, which is an important next step to ultimately understand how phage therapy may be used to replace antibiotics on a widespread scale.