RESEARCH METHODOLOGY POSTER PRESENTATION ABSTRACTS
Please note: All posters will be displayed in
Salons 10-12.
FRIDAY, 10:15-11:00 AM
Halcón L, Swiontkowski M, Tsukayama D, Theil
T.
Clinical research on essential oils as topical antimicrobials:
Tea tree oil wound pilot study results.
University of Minnesota halco001@umn.edu
PURPOSE: There has been a marked increase in
difficult to treat skin and underlying tissue infections associated
with Gram-positive bacteria, notably methicillin-resistant and -sensitive
Staphylococcus aureus. Many in vitro studies have demonstrated
the efficacy of Melaleuca alternifolia essential oil (tea tree
oil) against S. aureus; however, there is little published clinical
research in human populations. As part of an overall plan to evaluate
the efficacy of tea tree oil to treat skin and underlying tissue Staphylococcus
infections, this pilot study aimed to formulate an appropriate tea tree
oil wound care product and to assess a wound treatment protocol.
METHODS: The treatment formulation was an 8%
tea tree oil in poloxamer gel solution showing morphological stability.
The product was then tested using GC/MS over 12 months. Subjects with
chronic Staph-infected soft tissue wounds of 20 cm2 diameter
and under 1 cm depth were recruited from hospital based clinics and
were randomly assigned to the treatment or control (treatment with the
same product without tea tree oil) group. Study personnel were blinded
to treatment status; however tea tree oil has a characteristic smell
and subjects familiar with this odor might guess their status despite
identical packaging. Subject stratification provided for somewhat equal
numbers of patients with diabetes and using antibiotics in each group.
All subjects received usual care and were asked to follow the protocol
for four weeks with weekly follow-up visits for wound measurement and
monitoring. Blood tests were conducted to measure liver function, HbA1c,
and plasma terpene levels.
RESULTS: GC/MS analysis showed no significant
change in treatment gel composition over 12 months; however, there were
uniform decreases in chemical constituents, including the highly active
antimicrobial chemicals terpinen-4-ol and 1,8 cineole. Recruitment was
difficult, with only four subjects enrolled, three in the treatment
group and one control. Subjects completed daily logs and reported that
the protocol and measurements were acceptable. No adverse effects were
detected by hematologic tests and no terpenes were detected in the plasma
samples.
CONCLUSIONS: This pilot study provided important
pilot data. Results of GC/MS analysis suggest that this tea tree oil
gel suspension can be used 1 year after preparation; however, dose adjustment
may be needed due to uniform evaporation or degradation. The sample
size was insufficient to estimate effect size. Future protocols will
expand participation to those with acute wounds in addition to chronic
wounds and to include long term care and rehabilitation settings. The
absence of detected plasma terpenes suggests that tea tree oil is not
appreciably absorbed through wound applications. Future studies testing
antimicrobial effects of tea tree oil should include susceptibility
testing of clinical isolates.
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