In vitro activity of essential oils extracted from condiments against fluconazole-resistant and -sensitive Candida glabrata

In the present study, the antifungal activity of essential oils obtained from Origanum vulgare (oregano), Cinnamomum zeylanicum (cinnamon), Lippia graveolens (Mexican oregano), Thymus vulgaris (thyme), Salvia officinalis (sage), Rosmarinus officinalis (rosemary), Ocimum basilicum (basil) and Zingiber officinale (ginger) were assessed against Candida glabrata isolates. One group contained 30 fluconazole-susceptible C. glabrata isolates, and the second group contained fluconazole-resistant isolates derived from the first group after the in vitro induction of fluconazole-resistance, for a total of 60 tested isolates. The broth microdilution methodology was used. Concentrations of 50 mu g/mL, 100 mu g/mL, 200 mu g/mL, 400 mu g/mL, 800 mu g/mL, 1600 mu g/mL and 3200 mu g/mL of the essential oils were used, and the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. Thyme, sage, rosemary, basil and ginger essential oils showed no antifungal activity at the tested concentrations. Antimicrobial activity less than or equal to 3200 mu g/mL was observed for oregano, Mexican oregano and cinnamon essential oils. Both the oregano and Mexican oregano essential oils showed high levels of antifungal activity against the fiuconazole-susceptible C. glabrata group, whereas the cinnamon essential oil showed the best antifungal activity against the fluconazole-resistant C. glabrata isolates. (C) 2015 Elsevier Masson SAS. All rights reserved.