The inhibitory effects of tyrosol on clinical Candida glabrata planktonic and biofilm cells

Biofilm formation is an important problem in the healthcare industry and veterinary medicine and is very common in natural, industrial or hospital environments. Microorganisms can become very resistant to antimicrobials and environmental factors by biofilm forming on biotic or abiotic surfaces. There is a need to develop new, effective and specific antimicrobials that can reduce pathogenicity in biofilm formation that threatens public health due to their role in medical device-related or infectious diseases. Candida species are opportunistic pathogenic yeasts and can cause superficial or disseminated infections. Especially C. glabrata is one of the most common microorganisms causing fungal infections in immunocompromised patients and drug resistance is observed when associated with biofilm. Tyrosol (2-[4-hydroxyphenyl] ethanol) can act as both a quorum sensing molecule and an exogenous agent on Candida species. In this study, the antifungal activity of tyrosol against a clinical C. glabrata isolate was investigated on both planktonic and biofilm forms. Broth microdilution test results demonstrated the inhibitory effect of tyrosol on C. glabrata. Transmission electron microscopic findings showed that tyrosol affected the planktonic C. glabrata cells in a multi targeted manner, and in the groups treated with tyrosol, significant damage was observed in the cell wall, cell membrane, cytoplasm, nucleus and mitochondria. Also, scanning electron microscopic images confirmed biofilm reduction in pre-/post-biofilm applications as a result of tyrosol treatment. In conclusion, tyrosol may be a potential alternative candidate for reducing the C. glabrata biofilm.