Adhesion Behavior of Escherichia coli Strains on Glass: Role of Cell Surface Qualitative and Quantitative Hydrophobicity in Their Attachment Ability

Microbial adhesion to surfaces is thought to involve physicochemical interactions between the substrate and microbial cells. Understanding the physicochemical aspects involved in the adhesion phenomenon, as a critical step in biofilm formation, is essential to finding ways to prevent their formation and control biocontamination risks. The aim of this study was to investigate the relation between the adhesion behavior of 12 Escherichia coli strains isolated from food and their surface hydrophobicities using qualitative (θ(w)) and quantitative (ΔG(iwi)) approaches. The surface physicochemical properties of both bacterial cells and glass material were estimated through contact angle measurements. The adhesive behavior of E. coli strains on a glass surface was assessed. The results showed a good logarithmic relation between the percentage of the adhered cells and their surface hydrophobicity with the quantitative approach ΔG(iwi); however, qualitative hydrophobicity (θ(w)) appeared to demonstrate no effect regarding adhesion behavior. This work lays the foundation for future studies and opens an important debate on the mechanisms underlying the adhesion behavior of E. coli strains by using the thermodynamic approach (ΔG(iwi)) as an important model of hydrophobicity that could explain and predict better bacterial adhesion ability.