Background: Recent investigations on the antifungal properties of essential oil of Melaleuca alternifolia Cheel (Tea Tree Oil, TTO) have been performed with reference to the treatment of vaginal candidiasis. However, there is a lack of in vivo data supporting in vitro results, especially regarding the antifungal properties of TTO constituents. Thus, the aim of our study was to investigate the in vitro and the in vivo anti-Candida activity of two critical bioactive constituents of TTO, terpinen-4-ol and 1,8-cineole.

We report an outbreak of Saccharomyces cerevisiae subtype boulardii fungemia among three intensive care unit roommates of patients receiving lyophilized preparations of this fungus. The fungemia was probably due to central venous catheter contamination and resolved after fluconazole treatment. The need for stringent application of proper hygiene when using a probiotic preparation of this organism is emphasized. CASE REPORTSOutbreak cases. (i) Case 1. Case 1 involved a 34-year-old man hospitalized for hypoxia after head and thoracic trauma. He was placed on enteral nutrition, with insertion of a central venous catheter (CVC), and broad-spectrum antibiotic therapy was administered. On day 42 after admission (5 November 2000), he developed a fever, which was unsuccessfully treated with teicoplanin and imipenem. Multiple blood cultures yielded Saccharomyces cerevisiae. The fever and fungemia subsided under treatment with fluconazole at 400 mg/day. The CVC was removed 3 weeks after initiation of fluconazole treatment. The infectious episode resolved, but no catheter culture was performed.(ii) Case 2. Case 2 involved a 48-year-old man hospitalized for rupture of a cerebral aneurysm and fever. He was given enteral nutrition, and a CVC was inserted. Teicoplanin alone and then teicoplanin and meropenem were administered. On day 14 (10 November 2000), one blood culture yielded S. cerevisiae. On day 19, the CVC was removed and fluconazole therapy (400 mg/day) was immediately started. No catheter culture was performed. The fever subsided within 48 h of the initiation of fluconazole treatment.(iii) Case 3. Case 3 involved a 75-year-old woman admitted for acute myocardial infarction. She was given enteral nutrition, and a CVC was inserted. She was treated with various antibiotic regimens for several febrile episodes. On day 56 (10 April 2001), a blood culture yielded S. cerevisiae. The CVC was removed, leading to immediate defervescence. The CVC tip was positive for S. cerevisiae. Fluconazole therapy (400 mg/day) was started 2 days later and administered for 2 weeks.None of the three patients described above received any probiotic treatment. Case 4 (incomplete report).A 35-year-old woman with multiple traumas who had been hospitalized in the intensive care unit (ICU) at the same time as patients 1 and 2 had blood cultures positive for S. cerevisiae. Unfortunately, her medical record was sequestered for forensic purposes and whether she had received probiotic treatment or not could not be determined. This patient improved and was transferred to the orthopedic division, from which she was discharged 2 months later.The outbreak setting was an eight-bed ICU in a 400-bed secondary-care hospital in Rome, Italy. During the year preceding the outbreak, about 20% of the ICU patients were hospitalized for emergency surgery, 12% were hospitalized for elective surgery, 18% were hospitalized for trauma, and 50% were hospitalized for medical diseases. The mean (Ϯ standard deviation) age of patients was 66 Ϯ 16 years, the mean ICU hospitali...

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.

Oophorectomized, estrogen-treated rats were immunized by the intravaginal or intranasal route with a mannoprotein extract (MP) or secreted aspartyl proteinases (Sap) of Candida albicans, with or without cholera toxin as a mucosal adjuvant. Both routes of immunization were equally effective in (i) inducing anti-MP and anti-Sap vaginal antibodies and (ii) conferring a high degree of protection against the vaginal infection by the fungus. These data suggest that appropriate fungal antigens and adjuvant can be used to protect against candidal vaginitis, by either route.

BackgroundThe MP65 gene of Candida albicans (orf19.1779) encodes a putative β-glucanase mannoprotein of 65 kDa, which plays a main role in a host-fungus relationship, morphogenesis and pathogenicity. In this study, we performed an extensive analysis of a mp65Δ mutant to assess the role of this protein in cell wall integrity, adherence to epithelial cells and biofilm formation.ResultsThe mp65Δ mutant showed a high sensitivity to a range of cell wall-perturbing and degrading agents, especially Congo red, which induced morphological changes such as swelling, clumping and formation of hyphae. The mp65Δ mutant showed an activation of two MAPKs (Mkc1p and Cek1p), a high level of expression of two stress-related genes (DDR48 and SOD5), and a modulated expression of β-glucan epitopes, but no gross changes in cell wall polysaccharide composition. Interestingly, the mp65Δ mutant displayed a marked reduction in adhesion to BEC and Caco-2 cells and severe defects in biofilm formation when compared to the wild type. All of the mentioned properties were totally or partially recovered in a revertant strain, demonstrating the specificity of gene deletion.ConclusionsWe demonstrate that the MP65 gene of Candida albicans plays a significant role in maintaining cell wall integrity, as well as in adherence to epithelia and biofilm formation, which are major virulence attributes of this fungus.