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RIRDC Completed Projects in 2003-2004 & Research in Progress as at June 2004

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COMPLETED PROJECTS 2003-2004
Project No.	Project title	Researcher	Organisation	Phone No.
To improve understanding of markets for tea tree oil
UWA-75A	Compilation and review of published and unpublished tea tree oil literature	Prof Thomas Riley	University of Western Australia	08 9346 3690
RESEARCH IN PROGRESS 2003-2004
To enhance the ability of the industry to provide products that meet appropriate safety and efficacy
SAH-1A	Development of tea tree/ hydrogel dressings for use in wound care	Mr. Gary Bain	Sydney Adventist Hospital	02 9487 9785
UWA-79A	Tolerance of Pseudomonas aeruginosa to tea tree oil	Dr. Christine Carson	University of Western Australia	08 9346 3288
UWA-80A	Effects of tea tree oil on Staphylococcus aureus virulence factors	Prof Thomas Riley	University of Western Australia	08 9346 3690
To establish production systems that are both ecologically sustainable and profitable
DAN-199A	Breeding and cloning tea tree for greater profitability (continuation of DAN-151A)	Dr. Ian Southwell	NSW Department of Primary Industries	02 6626 1224
To improve existing products and develop new ones
UWA-72A	Assessing the in situ efficacy of tea tree oil as a topical antiseptic	Prof Thomas Riley	University of Western Australia	08 9346 3690


 
 

COMPLETED PROJECTS 2003-2004


 

Project Title	Compilation and review of published and unpublished tea tree oil literature
RIRDC Project No.:	UWA-75A
Researcher:	Prof Thomas Riley
Organisation:	University of Western Australia Microbiology (M502) School of Biomedical & Chemical Sciences 35 Stirling Hwy CRAWLEY WA 6009
Phone:	(08) 9346 3690
Fax:	(08) 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objectives	There are several outcomes proposed for this work. They are in order of priority: 1. a review published in a peer-reviewed journal and for RIRDC of the following for TTO: safety and toxicity, clinical efficacy 2. an assessment and/or review of the eco-toxicology of TTO based on direct and indirect data. If sufficient data are available a review will be published in a peer-reviewed journal and RIRDC report. 3. Conversion of tea tree oil literature into an electronic resource for researchers, industry participants and stakeholders 4. written recommendation for future TTO studies 5. production of Material Safety Data Sheets (MSDS) suitable for multiple importing destinations The dearth of information on some subjects (eg. eco-toxicology) may limit the degree to which current information may be reviewed but will enhance the scope for recommending future studies.
Background	No comprehensive collection of tea tree oil literature that could be distributed readily to industry stakeholders existed. Collation and review of the efficacy data, safety and toxicity data and the eco-toxicology data was also considered desirable and could reduce or eliminate future duplication of effort. Preparation of generic MSDS for TTO suitable for multiple importing destinations could simplify this regulatory requirement for many exporters.
Research	Methods consisted mainly of literature search strategies. Extensive searches of literature databases were undertaken and references of existing collections of tea tree oil publications were manually searched. At least one review article was prepared for publication.
Outcomes	The tea tree oil literature was reviewed focusing on the more recent literature but incorporating older publications for historical perspective. The ecotoxicity of tea tree oil was reviewed. The tea tree oil literature was compiled into a database designed to be accessible via the internet. A Material Safety Data Sheet (MSDS) was compiled from scientific publications, industry documents and various regulatory codes.
Implications	The industry has a single body of work available for easy reference. A contemporary review article will appear in the scientific literature. Gaps in the literature have been identified.
Publications	The review article will be published in a peer-reviewed scientific journal.


 
 

RESEARCH IN PROGRESS 2003-2004

To enhance the ability of the industry to provide products that meet appropriate safety and efficacy

Project Title	Development of tea tree/ hydrogel dressings for use in wound care
RIRDC Project No.:	SAH-1A
Start Date:	01-Jun-03
Finish Date:	29-Feb-04
Researcher:	Mr Gary Bain
Organisation:	Sydney Adventist Hospital Wound Clinic 185 Fox Valley Rd WAHROONGA NSW 2076
Phone:	02 9487 9785
Fax:	02 9487 9875
Email:	garyb@sah.org.au
Objectives	The objective of this project is to test a hydrogel wound dressing containing Tea Tree oil to determine if it provides relief and aids healing for specific types of wounds. It is proposed that this dressing should be targeted initially at the post radiotherapy skin reaction market with the view to investigating its value in the wider wound care market at a later date.
Current Progress (200 words maximum)	Data collection has been underway for two months. Thirty-four patients have currently consented to participate in the trial. Of these, seven patients have completed their treatment program (most treatment programs consist of around 30 treatments).  Data is being entered into the database as it is received. No preliminary analysis has been attempted due to the current small numbers. The research team is happy with the progress of the trial to date. Patients and staff have given positive and informative feedback about the trial, which will all contribute to the findings of this study.  The project is due to be completed by the 30 November 2004.

 

Project Title	Tolerance of Pseudomonas aeruginosa to tea tree oil
RIRDC Project No.:	UWA-79A
Start Date:	01-Jul-03
Finish Date:	01-Dec-04
Researcher:	Dr Christine Carson
Organisation:	University of Western Australia Microbiology, School of Biomedical & Chemical Sciences 35 Stirling Highway CRAWLEY WA 6009
Phone:	(08) 9346 3288
Fax:	(08) 9346 2912
Email:	ccarson@cyllene.uwa.edu.au
Objectives	The bacterium Pseudomonas aeruginosa is less susceptible to TTO than most other bacteria with MICs ranging from 2-10%. This project aims to characterise the mechanisms that P. aeruginosa uses to resist the inhibitory and cidal effects of tea tree oil (TTO) and components. Characterising the means by which P. aeruginosa avoids the toxic effects of TTO will provide more data on the mechanism of action of TTO. It will also begin to explore the issue of bacterial resistance to TTO and indicate whether this is likely to develop as TTO is used more widely. The range of mechanisms that may be responsible for the reduced susceptibility and that will be explored will include exclusion by the outer membrane, extrusion by efflux pumps, altered fatty acid composition and altered cellular hydrophobicity. This project will also explore the hypothesis that resistance to TTO is less likely to develop than resistance to individual components or conventional antibiotics. The identity of the mechanisms used will allow general predictions to be made about whether other bacteria are likely to become resistant to TTO.
Current Progress (200 words maximum)	Pseudomonas aeruginosa has been exposed to increasing concentrations of TTO and terpinen-4-ol. Isolates that tolerate 8% TTO and 7.5% terpinen-4-ol have been generated. Characterisation of these isolates included fatty acid analysis, antibiotic susceptibility profiles, hydrophobicity, outer membrane permeability and outer membrane protein analysis. Attempts to determine the spontaneous rate of mutation to TTO were unsuccessful due to the lipophilic nature of TTO that precluded use of the standard agar plate method. The inherent tolerance of wild-type organisms was explored using the outer membrane permeabilisers EDTA and PMBN. These compounds were able to augment the activity of TTO, terpinen-4-ol or ?-terpinene supporting previous suggestions that the outer membrane was important in this tolerance. The putative role of efflux pumps was considered by exposing cells to CCCP, and agent that depolarises bacterial cell membranes and diminishes energy production that is necessary to drive efflux pumps. CCCP treatment enhanced the effects of TTO and ?-terpinene suggesting that tolerance to these compounds is energy dependent.  Susceptibility data are being prepared for publication in a peer-review journal. Data on the inherent tolerance of P. aeruginosa have been accepted for publication in the Journal of Antimicrobial Chemotherapy.


 
 

Project Title	Effects of tea tree oil on Staphylococcus aureus virulence factors
RIRDC Project No.:	UWA-80A
Start Date:	01-Jul-03
Finish Date:	01-Dec-04
Researcher:	Prof Thomas Riley
Organisation:	University of Western Australia Microbiology (M502) 35 Stirling Hwy CRAWLEY WA 6009
Phone:	(08) 9346 3690
Fax:	(08) 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objectives	The aim of this research is to investigate and characterise the effects of tea tree oil on the production of virulence factors by Staphylococcus aureus, including methicillin-resistant isolates.
Current Progress (200 words maximum)	A collection of reference, clinical and methicillin-resistant isolates of S. aureus has been obtained. Isolates have been tested for their susceptibility to tea tree oil and screened for the production of virulence factors. Experiments investigating the production of extracellular protease, coagulase and toxins have been completed. Six isolates were investigated for the production of extracellular protease in the presence of tea tree oil. Levels of protease were significantly reduced by 0.016 and 0.031% tea tree oil for three of the six isolates only. Of the 12 isolates tested for the production of coagulase, four showed significantly increased levels after growth with 0.031% tea tree oil. For the remaining isolates levels were generally increased (not significant) or equivalent. Of the 10 isolates investigated for the production of toxin, nine showed a significant reduction in toxin titre after growth with 0.062% tea tree oil, but this concentration of tea tree oil also caused a significant decrease in the numbers of viable organisms, when compared to control cells. Experiments are currently being conducted investigating the formation of biofilm by S. aureus in polystyrene microtitre trays. Twenty isolates have been screened for biofilm production and the six isolates producing the highest levels have been selected for further investigation.


 

To establish production systems that are both ecologically sustainable and profitable

Project Title	Breeding and cloning tea tree for greater profitability (continuation of project DAN – 151A)
RIRDC Project No.:	DAN – 199A
Start Date:	01/07/2001
Finish Date:	30/06/2006
Researcher:	Dr. Ian Southwell
Organisation:	NSW Agriculture Wollongbar Agricultural Institute Bruxner Highway WOLLONGBAR NSW 2477
Phone:	(02) 66261224
Fax:	(02) 66283264
Email:	ian.southwell@agric.nsw.gov.au
Objectives	To improve the profitability of the tea tree industry by production and distribution of highly improved seed from a recurrent breeding strategy that ensures on-going improvement of seed quality. To release clones selected for high oil yield and quality from research linked to the breeding program studying the feasibility of utilising selected clones for plantation establishment.
Current Progress	For the seventh consecutive year, the tea tree breeding project has released seed to the industry. Seed made available is from best provenance, together with improved seed from both a seedling and clonal seed orchard. Over 200g ($80/g) of improved seed has been sold this year. First harvest gains from a yield trial established in 2002 to compare project released seed to other commercial seed, have been on average 70%. This gain was made up by a 20% increase in growth and a 40% increase in oil concentration. The best performing release was the clonal seed orchard seed which achieved a 91% increase in oil yield. Treatments will again be harvested this winter to assess the relative yield gains at second harvest. The project is on track for improvements greater than 100% from the second-generation seedling seed orchards (Wollongbar and West Wyalong). Assessment of plant growth and oil characteristics in the orchards will again be undertaken this year and inferior trees removed. For the first time, hybrid crosses with M. alternifolia and M. dissitiflora were performed during the 2003 flowering. The aim of these crosses is to establish hybrid progeny to study patterns of inheritance for components in the oil and growth potential of the hybrid. After extensive testing, suites of clones have been selected for their high yielding capacity. 10 elite clones have been mass propagated for field testing this spring with release of the best in 2005. Another suite of 15 clones (selected from 3 field trials established in 2002) has been prepared for propagation during 2004 for field testing in 2005.

To improve existing products and develop new ones

Project Title	Assessing the in situ efficacy of tea tree oil as a topical antiseptic
RIRDC Project No.:	UWA-72A
Start Date:	15-Jul-02
Finish Date:	14-Jul-04
Researcher:	Prof Thomas Riley
Organisation:	University of Western Australia Microbiology (M502) 35 Stirling Hwy CRAWLEY WA 6009
Phone:	(08) 9346 3690
Fax:	(08) 9346 2912
Email:	triley@cyllene.uwa.edu.au
Objectives	To examine the antimicrobial properties of tea tree oil based skin antiseptics by 3 different methods as well as an FDA approval hand wash evaluation. The study should show that the antibacterial effects demonstrated by tea tree oil are dependant on the method of assessment used. The ex- vivo method suggested is a closer approximation to the in-vivo situation and may take into account the skin penetrative properties of tea tree oil that cannot be assessed using traditional methods. A further objective is to conduct a clinical trial using a tea tree oil skin wash to reduce post- operative infections in surgical patients.
Current Progress (200 words maximum)	Due to the lack of antiseptics with sporicidal properties, the activity of tea tree oil (TTO)-containing products has been investigated according to the EN 14347 European suspension draft method. The activity of different concentrations of TTO in 0.001% Tween 80, as well as an alcoholic hygienic skin wash (AHSW) and an alcoholic handrub (AHR), was compared to the sporicidal disinfectants sodium hypochlorite (SH) and hydrogen peroxide (HP), and the antiseptic povidone iodine (PVI). These formulations were assessed after 30, 60 and 120 min against two strains of spore-forming bacteria: Bacillus cereus and Bacillus subtilis. The TTO formulated products and PVI did not achieve > 4 log10 reduction in spore counts, thus did not meet the European standard requirements. Nevertheless, 5%, 10% and 15% TTO in 0.001% Tween 80 significantly reduced the concentration of bacterial spores when compared with the water control, and were generally more effective than PVI. At a concentration of 15%, TTO was more active than 0.05% SH against spores of both strains after 30 min contact time, while 5% TTO in Tween 80 was generally more active than the AHSW that also contained 5% TTO. Further studies should be carried out to investigate the potential sporicidal activity of TTO directly on human skin in-vivo with volunteers and/or by using an "ex-vivo" test that uses freshly excised human skin and which would allow testing of any biocide as well any spore-forming bacterial strain, including pathogens. A paper based on these findings is about to be submitted.





Last updated: May 2005
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