In vitro and in vivo activity of tea tree oil against azole-susceptible and -resistant human pathogenic yeasts

• Published in: Journal of antimicrobial chemotherapy Vol. 51; no. 5; pp. 1223 - 1229
• Main Authors: Mondello, Francesca, De Bernardis, Flavia, Girolamo, Antonietta, Salvatore, Giuseppe, Cassone, Antonio
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2003; Oxford Publishing Limited (England)
• Subjects: animal model; Animals; Antibiotics. Antiinfectious agents. Antiparasitic agents; antifungal activity; Antifungal agents; Antifungal Agents - pharmacology; Azoles - pharmacology; Biological and medical sciences; Candida albicans - drug effects; Candida spp; Candidiasis, Vulvovaginal - drug therapy; Candidiasis, Vulvovaginal - microbiology; Drug Resistance, Fungal; Female; Fluconazole - pharmacology; Gas Chromatography-Mass Spectrometry; Humans; Itraconazole - pharmacology; Medical sciences; Microbial Sensitivity Tests; Mycoses - microbiology; Pharmacology. Drug treatments; Rats; Rats, Wistar; tea tree oil; Tea Tree Oil - chemistry; Tea Tree Oil - pharmacology; Yeasts - drug effects; Yeast; Cryptococcus neoformans; Fluconazole; Rat; Rodentia; Vaginal diseases; In vitro; Biological activity; Fungi; In vivo; Vertebrata; Antifungal agent; Chemotherapy; Vaginal route; Mammalia; Sensitivity resistance; Treatment; Animal; Candida; Triazole derivatives; Fungi Imperfecti; Thallophyta; Itraconazole
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkg202

A tea tree oil (TTO) preparation of defined chemical composition was studied, using a microbroth method, for its in vitro activity against 115 isolates of Candida albicans, other Candida species and Cryptococcus neoformans. The fungal strains were from HIV-seropositive subjects, or from an established type collection, including reference and quality control strains. Fourteen strains of C. albicans resistant to fluconazole and/or itraconazole were also assessed. The same preparation was also tested in an experimental vaginal infection using fluconazole–itraconazole-susceptible or -resistant strains of C. albicans. TTO was shown to be active in vitro against all tested strains, with MICs ranging from 0.03% (for C. neoformans) to 0.25% (for some strains of C. albicans and other Candida species). Fluconazole- and/or itraconazole-resistant C. albicans isolates had TTO MIC50s and MIC90s of 0.25% and 0.5%, respectively. TTO was highly efficacious in accelerating C. albicans clearance from experimentally infected rat vagina. Three post-challenge doses of TTO (5%) brought about resolution of infection regardless of whether the infecting C. albicans strain was susceptible or resistant to fluconazole. Overall, the use of a reliable animal model of infection has confirmed and extended our data on the therapeutic effectiveness of TTO against fungi, in particular against C. albicans.