Researchers shed light on MRSA treatment

06-Apr-2009 - Last updated on 07-Apr-2009 at 10:30 GMT

MRSA could be treated through a combination of an antimicrobial drug, a peptide and light, according to researchers who have hailed the treatment as a “magic bullet”.

The treatment is yet to enter clinical trials but the profile of methicillin-resistant Staphylococcus aureus (MRSA), which has been raised by media furor over its presence in hospitals, means that the positive laboratory results have been eagerly received.

Despite the levels of interest in MRSA its resistance to an array of antibiotics has hindered development of a treatment but researchers now believe they may have found a novel way of helping patients.

The researchers attached an antimicrobial agent, tin chlorin e6 (SnCe6), to a peptide that targets and binds to MRSA. Targeting the formulation with light, the wavelength of which has not been published, results in the production of free radicals and an unstable form of oxygen that damage and kill bacteria.

Linda Dekker, of University College London, said: “The results from laboratory studies are very encouraging and indicate that this technique might be effective at treating topical infections such as wound and burn infections.

“This work will require in vivo trials before it can be used. Due to the growing resistance of many organisms to antibiotics, this approach may be the only one available for use against microbes resistant to all known antibiotics.”

In the laboratory tests 99.97 per cent of 10m MRSA cells were killed, which the researchers claim is 1000 times more effective than treatment with tin chlorin e6 alone.

Furthermore the new treatment should result in less damage to human cells and MRSA is very unlikely to develop resistance to it, according to the researchers.

Illuminating drug delivery

The MRSA treatment was publicised a few days after a special issue of Photochemistry and Photobiology that examined the increasing prominence of light-activated drug delivery systems.

Researchers have seen promise in the use of light in the UV, visible and near-infrared range to activate materials sensitive to innocuous electromagnetic radiation.

As well as single-use delivery systems, which the MRSA treatment is an example of, researchers have also been working on materials capable of undergoing reversible structural changes, which would release a therapeutic in pulses in response to cycles of light and dark.