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BioMed Research International
Volume 2015 (2015), Article ID 456463, 7 pages
Research Article

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

1Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
2Department of Pharmaceutical Sciences, Faculty of Pharmacy, Princess Norah Bint Abdulrahman University, Riyadh 11671, Saudi Arabia

Received 11 September 2015; Revised 31 October 2015; Accepted 14 December 2015

Academic Editor: Stanley Brul

Copyright © 2015 Shaymaa Hassan Abdel-Rhman et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Mixed-species biofilms could create a protected environment that allows for survival to external antimicrobials and allows different bacterial-fungal interactions. Pseudomonas aeruginosa-Candida albicans coexistence is an example for such mixed-species community. Numerous reports demonstrated how P. aeruginosa or its metabolites could influence the growth, morphogenesis, and virulence of C. albicans. In this study, we investigated how the C. albicans quorum sensing compounds, tyrosol and farnesol, might affect Egyptian clinical isolates of P. aeruginosa regarding growth, antibiotic sensitivity, and virulence. We could demonstrate that tyrosol possesses an antibacterial activity against P. 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 in P. aeruginosa, whereas farnesol inhibits, to lower extent, hemolysin production in this bacterial pathogen. Cumulatively, tyrosol is expected to strongly affect P. aeruginosa in mixed microbial biofilm.