The role of hydrophobicity in bacterial adhesion

In biological systems, hydrophobic interactions are usually considered to be the strongest of all long-range non-covalent interactions. Considering hydrophobicity as the energy of interaction, ∆Giwi, between two entities (i) immersed in water (w): then a positive value means that i is hydrophilic, and when ∆Giwi has a negative value, i is hydrophobic. In other words, an increase in ∆Giwi means a decrease in hydrophobicity. The above concept was used in the interpretation of various adhesion experiments: (I) adhesion of a denitrifying strain (Alcaligenes denitrificans) to polymeric surfaces; (II) adhesion of an anaerobic consortium to porous microcarriers; (IV) adhesion of Staphylococcus epidermidis to polymeric materials, used in medical indwelling devices. In all the mentioned studies a linear correlation was obtained between the degree of hydrophobicity of the supporting surfaces and the number of adhered cells.