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A good old Aussie oil will help soothe a worsening modern headache if Dr Kate Hammer has her way.

In a study funded by the Rural Industries Research and Development Corporation, she is investigating whether tea tree oil can prevent the development of potentially disastrous antibiotic resistance.

“Resistance to antibiotics, including antibacterial and antifungal agents, is an enormous problem in health-care,” Dr Hammer from the School of Biomedical, Biomolecular and Chemical Sciences said.

The discovery of antibiotics revolutionised medicine last century and she is hoping tea tree oil will slow their relatively recent decline in efficacy due to increasing resistance. Her research will test the hypothesis that low levels of tea tree oil can slow the rate at which microorganisms become resistant to antibiotics, which are among the most prescribed drugs.

The usefulness of tea tree oil to treat ailments has probably been known in Australia since pre-history. The earliest reported use was by the Bundjalung Indigenous people of northern NSW who treated their coughs, colds and wounds with crushed eaves. Oral history also tells of healing lakes, which were lagoons in which tea tree leaves had fallen and decayed.

Legend has it that the oil was considered so important for its medicinal uses that it was supplied in the kits of Australian soldiers during World War II and that tea tree cutters were exempt from military service.

With her colleague Professor Tom Riley and the tea tree oil research group, Dr Hammer has already shown that tea tree oil is effective in combating common pathogens such as E.coli and golden staph bacteria, as well as yeasts, the fungi responsible for tinea, and anaerobic organisms – and her work will go further by testing the efficacy of the oil in reducing resistance acquisition, expanding the usefulness of antibiotics.

Dr Hammer explained that the oil destroys bacteria, fungi and anaerobic organisms by damaging their cell membranes beyond repair: “The oil molecules are small enough to insert into the lipid bilayer of the cells. This disruption of the physical barrier between the cell and its external environment may result in greater quantities of antibiotic entering the cell, meaning faster cell death and less opportunity for resistance to arise.

“Tea tree oil has more than 100 components, which may make it very difficult for organisms to evolve coping mechanisms.

“Because the oil is used in medicine only as an external application onto the skin, the top layer of which is made up of dead cells, the toxicity risk to patients is minimal.”
Her hope is that in the future some topically applied antibiotics will be administered as a combination therapy – a cream with a tea tree oil component. An example of a common combination therapy is the use of the non-antibiotic benzoyl peroxide combined with an antibiotic for the topical treatment of acne.

• From UWA News 16 November 2009