Suppression of inflammatory reactions by terpinen-4-ol, a main constituent of tea tree oil, in a murine model of oral candidiasis and its suppressive activity to cytokine production of macrophages in vitro.

The onset of oral candidiasis is accompanied by inflammatory symptoms such as pain in the tongue, edema or tissue damage and lowers the quality of life (QOL) of the patient. In a murine oral candidiasis model, the effects were studied of terpinen-4-ol (T-4-ol), one of the main constituents of tea tree oil, Melaleuca alternifolia, on inflammatory reactions. When immunosuppressed mice were orally infected with Candida albicans, their tongues showed inflammatory symptoms within 24 h after the infection, which was monitored by an increase of myeloperoxidase activity and macrophage inflammatory protein-2 in their tongue homogenates. Oral treatment with 50 µL of 40 mg/mL terpinen-4-ol 3h after the Candida infection clearly suppressed the increase of these inflammatory parameters. In vitro analysis of the effects of terpinen-4-ol on cytokine secretion of macrophages indicated that 800 µg/mL of this substance significantly inhibited the cytokine production of the macrophages cultured in the presence of heat-killed C. albicans cells. Based on these findings, the role of the anti-inflammatory action of T-4-ol in its therapeutic activity against oral candidiasis was discussed.

Susceptibility to Melaleuca alternifolia (tea tree) oil of yeasts isolated from the mouths of patients with advanced cancer.

Yeasts that are resistant to azole antifungal drugs are increasingly isolated from the mouths of cancer patients suffering from oral fungal infections. Tea tree oil is an agent possessing antimicrobial properties that may prove useful in the prevention and management of infections caused by these organisms. In this study, 301 yeasts isolated from the mouths of 199 patients suffering from advanced cancer were examined by an in vitro agar dilution assay for susceptibility to tea tree oil. All of the isolates tested were susceptible, including 41 that were known to be resistant to both fluconazole and itraconazole. Clinical studies of tea tree oil as an agent for the prevention and treatment of oral fungal infections in immunocompromised patients merit consideration.

Fungal susceptibility testing: where are we now?

Invasive fungal infections have been noted in increasing frequency in immunosuppressed patients and may be due to organisms that are less susceptible or frankly resistant to antifungal agents. Recently, standards have been established for testing both yeasts and moulds for susceptibility to antifungal agents. While these tests are increasingly available for clinical use, clinicians are faced with the challenge of whether these tests offer benefit in terms of management and when they should be obtained. In this review, the relevance of these tests is discussed, as are the clinical data, especially for yeasts, that support their use. In addition, the strategy of identifying yeasts to the species level as a means for predicting susceptibility is also discussed. While susceptibility testing of all fungal isolates is not necessary and not recommended, the judicious use of these tests and the role of the mycology laboratory in assisting in management of invasive fungal infection is also evaluated.

Treatment of oropharyngeal candidiasis in HIV-positive patients.

Most HIV-positive patients develop some form of oral candidiasis, most commonly pseudomembranous candidiasis, erythematous candidiasis, or angular cheilitis, at some point in their disease. All these manifestations are important risk markers for disease progression. Oral candidiasis is generally caused by Candida albicans. Although oral candidiasis can occur at any stage of HIV infection, it is most common in patients with low CD4 counts. Numerous oral and systemic therapies are used to treat oral candidiasis, the most popular of which are nystatin (topical), clotrimazole (topical), ketoconazole (systemic), fluconazole (systemic), and itraconazole (systemic). The topical agents are available in assorted dosage forms with varying degrees of efficacy and patient acceptability. The limited data currently available suggest an advantage for the systemic agents, although problems with resistance may limit the usefulness of fluconazole. The efficacy, safety, and cost effectiveness of a given agent must be considered when prescribing a specific agent for the treatment of oral candidiasis.

The relationship between immunological parameters and response to therapy in resistant oral candidosis.

Eight patients with resistant oral candidal infection have undergone full immunological assessment. In four of these patients no significant abnormality of immune function was observed, and all responded to intensive antifungal therapy with nutritional supplements of iron and folic acids as required. The remaining four patients had abnormalities only of specific candida-related immune function and no detectable abnormality of general immune function. Surgical excision of affected areas of oral mucosa was found to be the most effective therapy in three of these four cases. The immunological findings in these cases are compared with those observed in five patients with chronic mucocutaneous candidosis in whom both specific candida-related and non-specific immune incompetence were present.