Pseudomonas aeruginosa lipopolysaccharide enhances Candida albicans hypha specific gene expression

Abstract

Introduction: Demystification of cellular interactions in mixed biofilms has a major impact on therapeutics. Objective: Evaluation of the effect of bacterial lipopolysaccharide (LPS) on Candida albicans biofilm formation and its hyphal development. Method: The effect Pseudomonas aeruginosa LPS on C. albicans SC 5314 was studied using a standard biofilm assay. Biofilm formation of LPS treated C. albicans on polystyrene surfaces was quantified at 90min, 24h and 48h by a XTT reduction assay. Biofilms were qualitatively and quantitatively analyzed using Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). The effect of LPS on hypha specific genes (HSGs) of C. albicans was evaluated with quantitative Real time PCR. Farnesol, a natural pesticide, was also evaluated. Differential expression of HSGs; ECE1, HWP1, HYR1, RBT1, RBT4, ALS3 and ALS8 were assessed at 24h biofilms. Results: Adhesion of C. albicans (90 min) was significantly enhanced by P. aeruginosa LPS (P<0.05). CLSM and SEM further confirmed these data. All HSGs tested were significantly upregulated when treated with LPS and was significantly downregulated when treated with farnesol (p<0.05). Conclusion: P. aeruginosa LPS significantly enhances in vitro C. albicans hyphal development though it does not appear to affect the Candida biofilm metabolic activity.