Antifungal Activity of Lavandula angustifolia Essential Oil against Candida albicans: Time-Kill Study on Pediatric Sputum Isolates

Abstract

The aim of our study was to determine the susceptibility of 15 <i>Candida albicans</i> sputum isolates on fluconazole and caspofungin, as well as the antifungal potential of <i>Lavandula angustifolia</i> essential oil (LAEO). The commercial LAEO was analyzed using gas chromatography-mass spectrometry. The antifungal activity was evaluated using EUCAST protocol. A killing assay was performed to evaluate kinetics of 2% LAEO within 30 min treatment. LAEO with major constituents' linalool (33.4%) and linalyl acetate (30.5%) effective inhibited grows of <i>C</i>. <i>albicans</i> in concentration range 0.5-2%. Fluconazole activity was noted in 67% of the isolates with MICs in range 0.06-1 µg/mL. Surprisingly, 40% of isolates were non-wild-type (non-WT), while MICs for WT ranged between 0.125-0.25 µg/mL. There were no significant differences in the LAEO MICs among fluconazole-resistant and fluconazole-susceptible sputum strains (<i>p</i> = 0.31) and neither among caspofungin non-WT and WT isolates (<i>p</i> = 0.79). The 2% LAEO rapidly achieved 50% growth reduction in all tested strains between 0.2 and 3.5 min. Within 30 min, the same LAEO concentration exhibited a 99.9% reduction in 27% isolates. This study demonstrated that 2% solution of LAEO showed a significant antifungal activity which is equally effective against fluconazole and caspofungin susceptible and less-susceptible strains.