Tricking bacteria to consume a “Trojan horse” metal that looks like food but disrupts their ability to reproduce may be a way to defeat superbugs, say scientists.

Early studies in the US have shown that a single dose of the gallium molecule cured mice of lethal lung infections.

In human patients with cystic fibrosis, the new treatment was shown to improve lung function.

Scanning electron microscope image of Pseudomonas bacteria (Singh Lab, University of Washington/PA)Gallium is a metal similar to iron, a critical nutrient for bacteria – but instead of nourishing the bugs, it harms them.

Professor Bradley Britigan, a member of the research team from the University of Nebraska, said: “Gallium disrupts machinery that bacteria use to make new DNA, and without this the bacteria can’t multiply.

“This and other essential processes require iron, and gallium is a monkey wrench that shuts the system down.”

The study, reported in the journal Science Translational Medicine, focused on Pseudomonas aeruginosa, a microbe that causes lung infections.

The bug is a particular problem for patients with conditions such as cystic fibrosis, cancer and Aids whose immune systems are impaired.

In laboratory tests, bacteria only slowly developed resistance to gallium, and the metal’s potency was increased when combined with certain antibiotics.

The researchers investigated the effects of gallium in 20 patients with cystic fibrosis and hard-to-treat lung infections caused by a resistant strain of Pseudomonas.

Professor Christopher Goss, from the University of Washington, who co-led the research, said: “Our preliminary study in a small group of people with CF suggests that gallium is safe and improves patients’ lung function.

“These are exciting results, but we need to do more studies to determine if gallium can be developed into a routine, safe treatment.”