Publications (136) View all
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Dataset: TTO Paper 2012
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Article: In vitro Candida albicans biofilm induced proteinase activity and SAP8 expression correlates with in vivo denture stomatitis severity.
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ABSTRACT: Denture stomatitis is a common inflammatory disorder of the palatal mucosa amongst denture wearers. The pathological changes are induced by Candida albicans biofilm on the fitting surface of the upper denture, and different individuals experience different levels of disease. C. albicans is known to produce secreted aspartyl proteinases (SAPs) to aid adhesion, invasion and tissue destruction. We hypothesised that differential expression and activity of SAPs from denture stomatitis isolates results in different levels of disease amongst denture wearers. We selected C. albicans isolates from asymptomatic controls and three different severities of disease [Newton’s type (NT) 0, I, II and III]. We assessed biofilm formation and proteinase activity for each biofilm and investigated the transcriptional profile of SAPs 1, 2, 5, 6 and 8 from early (12 h) and mature (24 h) biofilms. There were no significant differences between isolates with respect to biofilm formation, whereas proteinase activity normalised to biofilm growth was significantly increased in the diseased groups (p < 0.0001). Proteinase activity correlated strongly with SAP expression (p < 0.0001). SAP8 expression was the greatest, followed by SAP5, 6, 2 and 1. The diseased groups showed the greatest levels of SAP expression, with significant differences also observed between the groups (p < 0.005). All SAPs except SAP5 were expressed in greater amounts in the mature biofilms compared to early biofilms. Overall, this study suggests that SAP activity in biofilms determined in vitro may help to explain differences in disease severity. SAP8 has been shown for the first time to play a prominent role in biofilms.Mycopathologia 02/2012; 174(1):11-19. · 1.65 Impact Factor -
Article: Carbohydrate Derived Fulvic Acid: An in vitro Investigation of a Novel Membrane Active Antiseptic Agent Against Candida albicans Biofilms.
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ABSTRACT: Carbohydrate derived fulvic acid (CHD-FA) is a heat stable low molecular weight, water soluble, cationic, colloidal material with proposed therapeutic properties. The aim of this study was to evaluate the antifungal activity of CHD-FA against Candida albicans, and to characterize its mode of action. A panel of C. albicans isolates (n = 50) derived from a range of clinical specimens were grown planktonically and as biofilms, and the minimum inhibitory concentrations determined. Scanning electron microscopy was performed to examine ultrastructural changes and different cell membrane assays were used to determine its mode of action. In addition, the role of C. albicans biofilm resistance mechanisms were investigated to determine their effects on CHD-FA activity. CHD-FA was active against planktonic and sessile C. albicans at concentrations 0.125 and 0.25% respectively, and was shown to be fungicidal, acting through disruption of the cell membrane activity. Resistance mechanisms, including matrix, efflux, and stress, had a limited role upon CHD-FA activity. Overall, based on the promising in vitro spectrum of activity and minimal biofilm resistance of the natural and cheap antiseptic CHD-FA, further studies are required to determine its applicability for clinical use.Frontiers in microbiology. 01/2012; 3:116. -
Article: Antifungal, cytotoxic, and immunomodulatory properties of tea tree oil and its derivative components: potential role in management of oral candidosis in cancer patients.
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ABSTRACT: Candida albicans forms oral biofilms that cause disease and are difficult to treat with conventional antifungal agents. Tea tree oil (TTO) is a natural compound with reported antimicrobial and immunomodulatory activities. The aims of the study were to evaluate the antifungal efficacy of TTO and key derivatives against C. albicans biofilms, to assess the toxicological effects of TTO on a clinically relevant oral cell line, and to investigate its impact on inflammation. TTO and its derivatives were examined against 100 clinical strains of C. albicans. Planktonic minimum inhibitory concentrations (MICs) were determined using the CLSI M-27A broth microdilution method. Sessile MICs were determined using an XTT reduction assay. Inhibition, time-kill, and mode of action studies were performed. OKF6-TERT2 epithelial cells were used for cytotoxicity and cytokine expression assays. Planktonic C. albicans isolates were susceptible to TTO, terpinen-4-ol (T-4-ol), and α-terpineol, with an MIC(50) of 0.5, 0.25, and 0.25%, respectively. These three compounds also displayed potent activity against the 69 biofilm-forming strains, of which T-4-ol and α-terpineol displayed rapid kill kinetics. For all three compounds, 1 × MIC(50) effectively inhibited biofilm growth when C. albicans were treated at 0, 1, and 2 h post adhesion. By scanning electron microscopy analysis and PI uptake, TTO and derivative components were shown to be cell membrane active. TTO and T-4-ol were cytotoxic at 1 × MIC(50), whereas at 0.5 × MIC(50) T-4-ol displayed no significant toxicity. Transcript and protein analysis showed a reduction of IL-8 when treated with TTO and T-4-ol. These data provide further in vitro evidence that TTO and its derivative components, specifically T-4-ol, exhibit strong antimicrobial properties against fungal biofilms. T-4-ol has safety advantages over the complete essential oil and may be suitable for prophylaxis and treatment of established oropharyngeal candidosis. A clinical trial of T-4-ol is worthy of consideration.Frontiers in microbiology. 01/2012; 3:220. -
Article: Commercial mouthwashes are more effective than azole antifungals against Candida albicans biofilms in vitro.
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ABSTRACT: The aim of this study was to evaluate and compare the activity of prescription and over-the-counter antimicrobial compounds against planktonic and biofilm forms of Candida albicans isolated from cases of oral candidiasis in vitro. The efficacy of azoles, polyenes, an echinocandin, and 4 over-the-counter mouthwashes were tested against C. albicans-derived planktonic and biofilm cells. Planktonic cells were shown to be highly sensitive to all of the antifungal agents tested. Sessile cells were highly resistant to azoles (≥128 mg/L) but equally sensitive to caspofungin and short treatments with Corsodyl, Listerine, and Oraldene. Although C. albicans is sensitive to azole antifungal agents in planktonic form, it is highly resistant within the biofilm. The good efficacy of the over-the-counter mouthwashes against candidal biofilms in vitro suggests that clinical trials should now be designed to establish their role in the clinical management of oral candidal infections.Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics 02/2011; 111(4):456-60. · 1.50 Impact Factor
