Media Release
March 6 2008
Native plants help fight implant infection
Every year about two million people are treated for infections
associated with surgical implants and biomedical devices such as
catheters, orthopaedic implants and contact lenses at a cost of more
than $11 billion in the United States alone.
Adverse consequences resulting from bacterial infections include
revision surgery, impaired quality of life of patients, serious health
complications and even death, particularly among elderly patients.
A team of UniSA researchers has identified a new route towards
infection-resistant coatings on biomedical devices by using novel
antibacterial chemicals extracted from native plants. Experiments have
shown that coatings of these chemicals prevented bacterial colonisation
and growth on materials.
Currently bacterial infections that colonise and grow on the surfaces of
implants and biomedical devices are protected by a biofilm layer that
develops and forms a protective barrier over the bacteria, making it
difficult to eradicate by administering antibiotics, according to
Ian Wark Research Institute Deputy Director,
Professor Hans Griesser, who is
leading the research.
“Our research involved attaching antibacterial compounds in thin layers
to the surfaces of plastic sheet model materials used for fabricating
biomedical devices, and then exposing the samples to bacteria. The
results were exciting. The materials coated with the native plant
compounds did not allow bacteria to settle, but bacteria happily
colonised the uncoated plastic surfaces,” Prof Griesser said.
Prof Griesser has been conducting research with
Sansom Institute
Research Fellow,
Dr Susan Semple, who led the project to extract and
identify antibacterial compounds from Australian plants of the genus
Eremophila using plant material collected from gardens or the wild, with
permits. Eremophila refers to “desert loving”, and these plants prefer
dry and arid areas. Some Eremophila species growing in arid areas of
Australia are used in traditional Aboriginal medicine.
“As little was known about the active chemicals in these plants, we
looked at a whole range of different species of Eremophila, before
focusing on plants with a protective resin coating on their leaves,
which we believed could be antibacterial,” Dr Semple said.
PhD student, Chi Ndi from the Sansom Institute,
School of Pharmacy and
Medical Sciences, screened more than 70 different Eremophila species and
hybrids and found some that were particularly active against bacteria
that cause human medical implant and device infections. Some of the
chemicals extracted by Chi Ndi were then coated onto plastics materials
by PhD student Hardi Ys from the Ian Wark Research Institute and in
collaborative research their antibacterial effectiveness has been
studied.
“To our knowledge nobody else in Australia is looking at the biomedical
applications of native plants. Having an antibacterial that is
completely different to current products being used does have an
advantage in that it’s not going to select for resistance to other
antibiotics that we need to treat infections,” Dr Semple said.
Being able to isolate compounds with antibacterial effects helps to
overcome the limitations of current technologies aimed at fighting
infection. It has the potential to deliver a breakthrough solution, with
enormous benefits for both human health care and Australian biomedical
device manufacturers.
“Some of our research was guided by Aboriginal medicine and an important
part of my work has been working with Indigenous people,” Dr Semple
said. “But we are not trying to take their medicines and patent them.
Our research focuses on the biomedical application in terms of surface
coatings, which is quite different to traditional usages,” she said.
“We would like to involve Indigenous communities in establishing and
managing the cultivation of the Eremophila species on farms in remote
communities and inland,” Dr Semple said.
“In some other antibacterials that we’ve worked with in the past, we’ve
encountered a very tight line between being effective against bacteria
and damaging human cells. The fact that some Eremophila species have
been used by Indigenous people suggested that there was a greater chance
that these could be safe,” Prof Griesser said.
“We are patenting a possible solution to implant infections based on
encouraging preliminary results and have estimated a two-year timeline
to obtain definitive results on the effectiveness of these compounds
when applied to several different types of biomedical devices,” he said.
“It’s an exciting glimpse of future possibilities, with a good package
of intellectual property including a patent and scientific data to
support our findings.”
Contacts for interview
- Professor Hans Griesser office (08) 8302 3703 email hans.griesser@unisa.edu.au
Media contact
- Geraldine Hinter office (08) 8302 0963 mobile 0417 861832 email geraldine.hinter@unisa.edu.au