Determination of the Antifungal Activity of Geraniol against Candida Tropicalis Isolates of pulmonary Origin

Abstract

Introduction: The prevalence of nosocomial infections caused by yeasts of the genus Candida has increased especially by non-albicans species. The superficialforms of candidiasis can evolve to systemic forms affecting different organs reaching the lower respiratory tract and giving rise to disseminated pulmonary candidiasis of complex diagnosis, difficult treatment and high mortality, due to the limited arsenal of antifungals that forces to look for new alternatives, in which monoterpenes derived from plants have shown antifungal potential.

Objective: To evaluate the antifungal activity of the monoterpene geraniol against Candida tropicalis isolates of pulmonary origin.

Methods: The microdilution technique was used to determine the minimum inhibitory concentration and the minimum fungicidal concentration of geraniol. In addition, the impact of geraniol and amphotericin B on fungal micromorphology and time to death against Candida tropicalis strains was evaluated.

Results: Geraniol showed inhibitory concentration of 32-64 μg/mL and a minimum fungicidal concentration of 128-256 μg/mL. Geraniol (64 μg/mL) inhibited the appearance of virulence structures such as pseudo hyphae and reduced ballistoconidia formation in the micromorphology assay. The results showed that geraniol is concentration-dependent fungicidal.

Conclusions: The monoterpene geraniol showed significant fungicidal activity against pulmonary isolates of Candida tropicalis and inhibited the appearance of fungal virulence structures, with concentration-dependent efficacy.