Effects of Farnesol on Drug-Resistant and Non-Resistant <i>Candida albicans</i>: Implications for Cosmetic and Pharmaceutical Applications

Abstract

Background: Farnesol is added to numerous consumer products that intentionally, or inadvertently come in contact with tissues that may harbor the opportunistic yeast, Candida albicans. Objective: This study explores biological consequences of the exposure of Candida albicans from community infections or from a panel of antifungal drug resistant organisms on growth and survival of these organisms when exposed to farnesol. Methods: ATCC supplied Candida albicans from the MP8 drug resistance panel and an additional 12 strains of community-acquired Candida albicans were cultured in the presence of farnesol. With standard micobiologic techniques and flow cytometry evaluation, a series of experiments considered growth, morphology, viability and entrance into the quiescent persister phenotype of Candida with emphasis on differences between drug resistant and community organisms. Results: Differences growth yield, relative cell size and heat susceptibility distinguished the community organisms from the drug-resistant organisms. Using a subset of these organisms, exposure to farnesol resulted in diminished growth, inhibited hyphal growth, diminished cell membrane integrity and increased heat stress susceptibility. Data provided suggest that exposure to farnesol pushes cultures of Candida albicans toward the quiescent persister phenotype. Conclusion: Exposure of drug resistant and community strains of Candida albicans are modestly affected by farnesol in ways that may lessen their pathogenic potential. In contrast, the tendency of farnesol to engender greater numbers of quiescent organisms could support persistence of Candida.