The problem of superbug resistance to antibiotics is being combated through the creation of a virus that attacks the bacteria's defence systems.
Researchers from the Massachusetts Institute of Technology created viruses which target the bugs' DNA repair system. When used alongside antibiotics, the "bacteriophages" wipe out bacterial defences and prevent resistence from developing.
In an article in the journal Proceedings of the National Academy of Sciences, lead researcher Dr Timothy Lu said: "There are a lot of targets to go after, but people haven't been able to find the drugs. It's much easier to modify phages than to invent a new drug."
A study tested the virus with quinolone, beta-lactam and aminoglycloside antibiotics in infected mice and and found they had an 80% survival rate.
Mice treated with natural bacteriophages and antibiotics recorded a 50% survival rate, while only 20% survived when only treated with antibiotics.
Dr Lu said: "This work lays the groundwork for the development of a library of bacteriophages, each designed to attack different bacterial targets."