NZ scientist helps in superbug battle

Doctor Linda Dekker is part of the team testing a drug which could curtail the threat of the MRSA superbug. Photo / Supplied

A New Zealand scientist is part of a team testing a "light-activated" drug that could end the threat of the antibiotic-resistant MRSA superbug.

Linda Dekker, 27, educated at Otago University and now working in London, told a British conference of the effectiveness of a drug in killing MRSA (methicillin resistant staphylococcus aureus).

In New Zealand, the incidence of "superbug" infections has risen sharply in the past 20 years. Their treatment is far more complex and costly. Superbugs are a particular problem in hospitals where they can spread to other patients and staff.

Ms Dekker's group chemically joined a light-activated drug, tin chlorin e6, to a protein fragment. The protein fragment fits the shape of a molecule found on the surface of MRSA.

On its own, the drug, once exposed to light of the right frequency, can kill MRSA cells but, potentially, also human cells. Its combination with the protein fragment puts it closer to the target cells and is expected to prevent it from harming human tissue.

"When attached to the protein fragment, it will kill just the bacteria, because it can attach to the bacteria and get closer to it, hence more-localised killing," Ms Dekker told the Weekend Herald.

In laboratory tests, the combined drug killed almost 100 per cent of MRSA cells and was vastly more effective than using the drug without the protein fragment. The protein fragment suppressed the bug's potentially lethal production of toxins.

"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."

But it would need to be proven in animals before it could be considered for human clinical trials.

Head of the group, Professor Sean Nair, said they had developed light-activated therapy as a new way of killing superbugs. It had great potential.

The research presented by Ms Dekker was one of several potential MRSA treatments the group was involved in. One was already in a clinical trial.

Auckland pathologist and clinical microbiologist Dr Arthur Morris said up to 8 per cent of staph aureus infections in the region were MRSA and some were resistant to antibiotics.

He said the study presented by Ms Dekker was an exciting development that could open up a whole new way of treating MRSA, one that was unlikely to be rapidly overtaken by increased resistance as the bug evolved.

There were an estimated 8000 cases of MRSA in New Zealand in 2007. The bacteria can cause skin abscesses, post-operative wound infections and pneumonia and, through the toxins it produces, toxic shock syndrome.