Thermodynamic Analysis of Growth Temperature Dependence in the Adhesion of Candida parapsilosis to Polystyrene

Abstract

The purpose of this work was to study the adhesion to polystyrene of two Candida parapsilosis strains, grown at 22 and 37°C, in terms of hydrophobicity, surface charge, and interaction free energy. Growth temperature changed the surface properties of microorganisms, yielding a good correlation between thermodynamic predictions and adhesion behavior.Candida parapsilosis has emerged as an important nosocomial pathogen (16,20,24) with clinical implications, all of which usually occur in association with invasive procedures or prosthetic devices (27). Colonization by candidas and subsequent infection is achieved by a combination of specific (ligand-receptor interactions) and nonspecific mechanisms (1), allowing the yeast to attach to a wide range of tissue types and nonbiological surfaces. This process depends on the cell surface properties of both the host and the fungus (4).The main nonspecific forces acting during the initial stages of the adhesion process have a thermodynamic nature, and they are mainly related to the hydrophobic effect (11). The contribution of the electrostatic forces to adherence has been questioned (12).Quantification of surface hydrophobicity and surface charge can be made by different methods (3,21,26), but the obtained results are greatly influenced by the environmental conditions in which cells are grown or suspended in experimental procedures (7,8,9,10,19).The aim of this work is to study the hydrophobicity and surface charge of C. parapsilosis in relation to the process of adhesion to polystyrene, in order to determine whether the thermodynamic theory predicts the adherence. The effect of growth temperature on the above properties has been also analyzed.C. parapsilosis strain 294 and C. parapsilosis strain 289 were isolated from blood of patients of Infanta Cristina Hospital (Badajoz, Spain). Yeasts were stored at Ϫ80°C and cultured in Sabouraud broth at 22 and 37°C for 48 h. After culture, the yeasts were harvested by centrifugation, 5 min at 1,000 ϫ g (Sorvall TC6; Dupont, Newtown, Conn.), and washed three times in deionized water, potassium phosphate buffer (KPi) (0.01 mol liter Ϫ1 ) or phosphate-buffered saline (PBS) (0.1 mol liter Ϫ1 ) depending on the liquid employed in the experimental hydrophobicity assay. Finally, the cells were resuspended in the appropriate fluids.Water, formamide, and diiodomethane contact angles ( W , F , and D , respectively) on lawns of partially dried yeasts were determined using the sessile drop technique (3) ( Table 1). Briefly, microorganisms suspended in demineralized water were layered onto 3-m-pore-size filters (Millipore; Molsheim, France) using a negative pressure. The filters were left to air dry for 30 min and introduced into an environmental chamber, which was allowed to saturate with vapor from the liquid employed. The images were taken as has been described previously (15). Once the contact angles were measured, the Lifshitz-van der Waals (␥ LW ) and acid-base (␥ AB ) surface tension components were obtained from the application of the You...

Towards real-time observation of conditioning film and early biofilm formation under laminar flow conditions using a quartz crystal microbalance

“…An earlier study suggested that cell metabolism appeared to be essential for the maintenance of cell adhesion at higher temperatures [41]. However, it should be stressed that the effect of growth temperature on the initial microbial adhesion is also shown to be strongly dependent on the bacterial strain [42]. Previous studies involving the characterization of nonspecific bacterial adhesion to biomaterial surfaces observed that the initial cell adhesion and reversible cellular association with the surface occurred after a lag period of about 1-2 h [43,44].…”

Exposure of Escherichia coli ATCC 12806 to Sublethal Concentrations of Food-Grade Biocides Influences Its Ability To Form Biofilm, Resistance to Antimicrobials, and Ultrastructure

“…These modifications may result in a change in cell surface hydrophobicity. The hydrophobicity of the microbial cell surface plays a critical role in the adherence of bacteria to a wide variety of hydrophobic surfaces (e.g., polystyrene) (33,34). Because adherence of bacteria to the surface is the first step in biofilm formation, it is expected that an increase in cell surface hydrophobicity is accompanied by nonadapted treated cells; (G and H) adapted treated cells.…”

Potential of the adhesion of bacteria isolated from drinking water to materials

“…In drinking water distribution systems, microbial adhesion will initiate biofilm formation, exacerbating contamination of drinking water, reducing the aesthetic quality of potable water, increasing the corrosion rate of pipes sion step can be interpreted in terms of Lifshitz-van de Waals forces (LW) and acid-base forces (AB) (Smets et al 1999, Gallardo-Moreno et al 2002a. When a microorganism and a surface enter into direct contact the water film present between the interacting entities has to be removed.…”