1.Introduction. Cryptococcus neoformans is the etiological agent of cryptococcosis, a cosmopolitan infectious disease that affects humans, domestic and wild animals. It usually causes infection and disease in immunosuppressed patients. For treatment of cryptococcal infections in these patients, intravenous amphotericin B combined with flucytosine, followed by azole such as fluconazole (FLC) and itraconazole (ITZ) are recommended. Since the current therapies have certain limitations due to side effects such as toxicity, nephrotoxicity and emerging of resistant strains, effective treatments and the development of novel antifungal drugs will be necessary for the future. The essential oils (EO) had a wide application in folk medicine, fragrance industries, food flavoring and preservation, and in recent years, they have started to be recognized for their antimicrobial properties. The object of this study was to evaluate the antifungal activity of different EO and their major components alone and in combination with ITZ against some clinical isolates of C.neoformans, with different susceptibility or resistance patterns to FLC and voriconazole (VRZ). 2.Materials and methods. Antifungal activity (minimum inhibitory/fungicidal concentration, MIC/MFC) of thyme red, clove, pine, lemon balm, sage, lavender, fennel EO and some components (carvacrol, thymol,α-pinene) was evaluated in vitro against C.neoformans FLC/VRZ-susceptible (FLC/VRZ-S) and FLC/VRZ-resistant (FLC/VRZ-R) strains by a broth microdilution method, according to the CLSI. Moreover, the potential synergistic action of different OE and ITZ was evaluated by the checkerboard assay and calculation of the Fractional Inhibitory Concentration (FIC) Index. 3.Results. The results showed that most of EO and their major components displayed low MIC (% v/v) and possessed a significant fungicidal activity against C.neoformans FLC/VRZ-S and FLC/VRZ-R strains. The results also showed a significant synergistic relationship between some EO (e.g.thyme) and ITZ, with a consequent reduction of the MIC values of both compounds used in combination. 4.Discussion and conclusions. These results help to broaden the knowledge on antifungal action of EO, in view of the development in the future of new therapeutic strategies that favor the resolution of fungal infections and containment of toxicities and drug resistance.
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