Effect of Tyrosol and Farnesol on Virulence and Antibiotic Resistance of Clinical Isolates ofPseudomonas aeruginosa

Abstract

Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions.Pseudomonas aeruginosa-Candida albicanscoexistence is an example for such mixed-species community. Numerous reports demonstrated howP. aeruginosaor its metabolites could influence the growth, morphogenesis, and virulence ofC. albicans. In this study, we investigated how theC. albicansquorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates ofP. aeruginosaregarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity againstP. aeruginosa(10 µM inhibited more than 50% of growth after 16 h cultivation). Moreover, we could show for the first time that tyrosol strongly inhibits the production of the virulence factors hemolysin and protease inP. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affectP. aeruginosain mixed microbial biofilm.