Exogenous tyrosol inhibits planktonic cells and biofilms of Candida species and enhances their susceptibility to antifungals

Abstract

Tyrosol is a quorum-sensing molecule of Candida albicans able to induce hyphal development in the early and intermediate stages of biofilm growth. In the present study, we evaluated the effect of high concentrations of exogenous tyrosol on planktonic cells and biofilms of C. albicans (n = 10) and C. tropicalis (n = 10), and investigated whether tyrosol could be synergic to antifungals that target cellular ergosterol. Antifungal susceptibility and drug interaction against planktonic cells were investigated by the broth microdilution method. Tyrosol was able to inhibit planktonic cells, with MIC values ranging from 2.5 to 5.0 mM for both species. Synergism was observed between tyrosol/amphotericin B (11/20 strains), tyrosol/itraconazole (18/20 strains) and tyrosol/fluconazole (18/20 strains). Exogenous tyrosol alone or combined with antifungals at both 10 × MIC and 50 × MIC were able to reduce biofilm of both Candida species. Mature biofilms were susceptible to tyrosol alone at 50 × MIC or combined with amphotericin at both 10 × MIC and 50 × MIC. On the other hand, tyrosol plus azoles at both 10 × MIC and 50 × MIC enhanced biofilm growth.

Activity of exogenous tyrosol in combination with caspofungin and micafungin against Candida parapsilosis sessile cells

“…Cordeiro et al . () showed that exogenous tyrosol in supraphysiological concentration (2·5–5 mmol l −1 ) significantly inhibits the growth of planktonic C. albicans and C. tropicalis isolates. Present study has found no inhibitory effect of tyrosol against C. parapsilosis planktonic cells.…”

“…Furthermore, Cordeiro et al . () reported synergistic interactions of tyrosol with amphotericin B and azoles against C. albicans and C. tropicalis planktonic cells based on FICI determination. Unlike these findings, current study using tyrosol combined with caspofungin or micafungin against C. parapsilosis planktonic cells has not found synergistic interactions.…”

“…Paradoxically at the same time, as described before, it may have an inhibitory effect alone or in combination with traditional antifungals on biofilm formed by C. albicans and C. tropicalis (Cordeiro et al . ; Monteiro et al . ).…”

Effect of quorum sensing molecules and natamycin on biofilms of Candida tropicalis and other yeasts isolated from industrial juice filtration membranes

“…The ability of these molecules to disrupt yeast biofilms is currently being studied in the clinical field (Wongsuk et al 2016). Additionally, the combination of antifungals with QS molecules has been studied especially against Candida albicans biofilms (Shanmughapriya et al 2014;de Cordeiro et al 2015;Katragkou et al 2015;Boz o et al 2016;Kov acs et al 2016). To the best of our knowledge, there is no information available about the effectivity of combinatory treatments against yeast biofilms inhabiting food and food processing devices.…”

Interspecies Interactions between Clostridium difficile and Candida albicans

“…It is tempting to speculate that a similar mechanism contributes to the action of p -cresol. Notably, several other phenolic compounds have been reported to positively or negatively affect Candida viability, morphology, and biofilm formation; these include but are not limited to tyrosol (67, 68), p -coumaric acid (69), ferulic acid (70), caffeic acid (71), boric acid (72), and eugenol (73). These observations, together with the identification of more-complex inhibitors (74, 75), may lead to the identification of general structural principles of compounds that govern Candida proliferation and the yeast-to-hypha transition.…”