Analysis of the hydrophobic behaviour of different strains of Candida parapsilosis under two growth temperatures

Abstract

Several studies exist on the hydrophobicity of different strains of Candida albicans, but little is known about the hydrophobic characteristics of Candida parapsilosis, despite the fact that this species is becoming an important pathogen. This study shows that a large number of strains of C. parapsilosis do not exhibit the general hydrophobic behaviour of other species of candida under the same incubation temperatures. Various experimental assays were employed to discern the hydrophobic characteristics of the different strains studied. Adhesion to p-xylene did not present differences between the high hydrophobicity of C. parapsilosis 294 cultured at 22 and 37 °C (the percentage of adhesion to p-xylene was near to 100% in both cases), while water contact angle showed this strain to be more hydrophobic at the highest growth temperature ( ϑ W(37 °C)=50°; ϑ W(22 °C)=38°) with a good correlation to the increase of the adhesion to hexadecane and chloroform in this case. These methods revealed the same hydrophilic character of C. parapsilosis 289 ( ϑ W(37 °C)=22°; ϑ W(22 °C)=26°), and this was also reflected in the low adhesion to both solvents. A thermodynamical analysis based on interfacial interaction free energies was applied to the adhesion of yeasts to hexadecane and chloroform. The relative intensity of the yeast–water–solvent interaction free energy against solvent–water–solvent interaction free energy is presented as a useful relation to predict the adherence of the cells, and gave good results for the most hydrophobic strain 294 at both culture temperatures.