GALLIUM

Scottish scientists may have discovered a ‘silver bullet’ in winning the war against infection.

For some time now it has been feared that antibiotics are becoming increasingly powerless in the face of lethal bacteria which are developing resistance to the drugs.

The latest breakthrough, however, suggests that a revolutionary new treatment could turn the tide.

Scientists and researchers from the Universities of Edinburgh and Zurich, in Switzerland, found that germs are not only killed off by the element gallium but that they also struggle to evolve into resistant strains.

In tests carried out, the metal was pared against a highly-resistant bacterium commonly found in hospitals which can cause pneumonia and septic shock.

The researchers noted that the bug continued to multiply when faced with antibiotics but stalled when it came up against gallium.

Scientists also found that three-quarters of infected moth larvae survived when given the treatment compared with only 5 per cent of those which went without.

The study states: ‘Crucially, while resistance soon evolved against conventional antibiotic treatments, gallium treatments retained their efficacy over time.’

It adds: ‘In light of our results, we contend that this approach could curb microbial virulence… and therefore represents a promising alternative to our dwindling succession of traditional antibiotics.’

The team behind the research said they hoped their work would lead to a new breed of drugs.

The team’s lead author, Dr Adin Ross-Gillespie, said:

… It’s crucial that alternatives to antibiotics are found. Humanity is facing what has been described as a catastrophic threat: conventional antibiotics are losing efficacy due to the worldwide rise and spread of multi-drug resistant bacteria and very few new antibiotics are on the horizon.

The key to gallium’s success is its chemical similarity to iron, which bacteria cells need to flourish.

They send out molecules, called siderophores, which search for and track down the essential nutrient.

These are then tricked into binding with gallium instead. As the cells become starved of iron, they dispatch even more siderophores, a process which eventually wears them out.

Gallium’s subtler approach limits the chances of a resistant strain evolving. Unlike antibiotics, it works outside of the cell so the odds are slim of a mutation which survives and then evolves further.

Last year, Scotland’s chief medical officer, Sir Harry Burns, wrote to all health boards in Scotland warning of increasing numbers of bugs resistant to the most powerful antibiotics. There was only one such case in 2007, but 25 cases in 2012.

ABOUT GALLIUM:

Gallium is a soft, silvery metal which forms a brittle solid at lower temperatures.

The heat of a human hand is enough to convert it into a shiny liquid that at first glance resembles mercury. This is because the melting point is usually low for a metal, being about 29.76c – only a few degrees above the usual room temperature of about 21c.

Gallium was first isolated in its elemental form in 1875 by French scientist Paul Emile Lecoq de Boisbaudran, who named it after the Latin name for his homeland, Gallia.

Despite its ability to interfere with cells’ uptake of iron, gallium is not normally considered toxic in low doses.