A novel approach in the extract of Melaleuca alternifolia as a potential topical treatment of cutaneous Aspergillus ustus infections

School Name

Spring Valley High School

Grade Level

10th Grade

Presentation Topic

Microbiology

Presentation Type

Non-Mentored

Written Paper Award

2nd Place

Abstract

Primary cutaneous aspergillosis (PCA) is a serious concern for immunocompromised patients, with poor prognosis and high rates of dissemination and recurrence. The current treatment methods for PCA, surgical debridement and systemic antifungal therapy, are often ineffective, even when used in conjunction with one another. Infections by Aspergillus ustus are particularly threatening, as A. ustus is resistant to many currently used antifungals. Tea tree oil (TTO) is a natural extract from the Australian shrub Melaleuca alternifolia, and a large body of evidence supports its antimicrobial activity. As such, TTO was tested in vitro as a potential antifungal agent against A. ustus. A broth microdilution assay was conducted for 48 hours using the concentration range of 0.25% to 16% TTO, along with positive growth and negative growth controls, in order to determine the minimum inhibitory concentration (MIC). Afterwards, a spectrophotometric time-kill assay was conducted using the MIC, 2 x MIC, and 0.5 MIC values, with aliquots of the TTO solutions taken at 0, 24, and 48 hours. The MIC was determined at 4% TTO from the broth microdilution assay, with a Kruskal-Wallis test displaying statistical significance, X2 (8, N = 8) = 60.375, p < 0.0001. Additionally, a post hoc Dunn test found a significant difference between 4% TTO and the positive growth control (p = 0.001). The time-kill assay exhibited a decline in optical density for the 8% TTO between 0 and 48 hours. However, the 2% and 4% TTO solutions displayed a resurgence in growth after an initial decrease in optical density at 24 hours. Overall, the results demonstrated antifungal efficacy of TTO, while also indicating that TTO loses potency after prolonged periods of use at lower concentrations. These results and others further warrant the use of TTO as a topical agent for PCA.

Location

Wall 224

Start Date

3-25-2017 9:15 AM

Presentation Format

Oral and Written

Group Project

No

COinS
 
Mar 25th, 9:15 AM

A novel approach in the extract of Melaleuca alternifolia as a potential topical treatment of cutaneous Aspergillus ustus infections

Wall 224

Primary cutaneous aspergillosis (PCA) is a serious concern for immunocompromised patients, with poor prognosis and high rates of dissemination and recurrence. The current treatment methods for PCA, surgical debridement and systemic antifungal therapy, are often ineffective, even when used in conjunction with one another. Infections by Aspergillus ustus are particularly threatening, as A. ustus is resistant to many currently used antifungals. Tea tree oil (TTO) is a natural extract from the Australian shrub Melaleuca alternifolia, and a large body of evidence supports its antimicrobial activity. As such, TTO was tested in vitro as a potential antifungal agent against A. ustus. A broth microdilution assay was conducted for 48 hours using the concentration range of 0.25% to 16% TTO, along with positive growth and negative growth controls, in order to determine the minimum inhibitory concentration (MIC). Afterwards, a spectrophotometric time-kill assay was conducted using the MIC, 2 x MIC, and 0.5 MIC values, with aliquots of the TTO solutions taken at 0, 24, and 48 hours. The MIC was determined at 4% TTO from the broth microdilution assay, with a Kruskal-Wallis test displaying statistical significance, X2 (8, N = 8) = 60.375, p < 0.0001. Additionally, a post hoc Dunn test found a significant difference between 4% TTO and the positive growth control (p = 0.001). The time-kill assay exhibited a decline in optical density for the 8% TTO between 0 and 48 hours. However, the 2% and 4% TTO solutions displayed a resurgence in growth after an initial decrease in optical density at 24 hours. Overall, the results demonstrated antifungal efficacy of TTO, while also indicating that TTO loses potency after prolonged periods of use at lower concentrations. These results and others further warrant the use of TTO as a topical agent for PCA.