Decoy makes drug effective against super bug

A DNA-based therapy could speed the development of effective drugs to combat antibiotic-resistant super bugs.

Scientists from the John Innes Centre (JIC) have proved they can switch off antibiotic resistance by taking a short stretch of DNA from a bacterium and delivering it with an existing antibiotic.

“The DNA sequence acts as a decoy, disrupting gene expression and blocking resistance,” said Dr Michael McArthur from JIC.

“We are putting genetic information directly into drugs. This is the first application of a DNA-based therapy.”

The scientists have also patented a way of discovering decoys in bacteria without necessarily having to know the genes involved. This means they can develop effective new drugs against any bacterium within a couple of years and at a fraction of the normal cost.

The technology can give fresh patent life to existing antibiotics — the old antibiotic can be patented as a new drug when combined with a decoy.

This could breathe some much-needed life into the pharmaceutical industry, which faces a dramatic reduction of new approved antibiotics accompanied with increasing bacterial resistance to current drugs.

“Natural resistance will always be hot on the heels of a new antibiotic because bacteria evolve,” said McArthur.

“Ours is not a traditional pharmaceutical approach and provides a completely new challenge to bacteria.”

The technology could improve the production of enzymes and other compounds using bacteria for use in industrial processes. Many industrial processes are harsh and unsustainable, using petrochemicals, high temperatures and creating toxic by-products. In industrial biotechnology, bacteria make medically and commercially important compounds biologically.

“By using bacteria, many industrial processes could be cleaned up,” said McArthur.

The scientists found that the bacterium Streptomyces produces a particularly high yield of enzymes and proteins. It can also secrete the proteins it produces, simplifying the extraction process.

“Streptomyces is the enzyme-producing bacterium with bells and whistles, set to make a major contribution to a market already predicted to be worth £400 million by 2010,” said McArthur.

Together with technology transfer company PBL, the scientists have launched a spin-out company, Procarta Biosystems, to develop the technology.