The Influence of EPS Conditioning Films on Pseudomonas aeruginosa Adhesion to Solid Surfaces

Abstract

Bacterial adhesion to inert surfaces in aquatic environments is highly dependent on the surface properties of the substratum, which could be altered significantly by the formation of conditioning films. The impacts of extracellular polymeric substances (EPS) and its several representative components of conditioning films on the initial adhesion of the wild type Pseudomonas aeruginosa PAO1 were investigated under four different conditions of ionic strength. Our results showed that bacterial adhesion to bare slides and slides coated with alginate or humic substances increased with the ionic strength. Conversely, BSA and extracted EPS coating enhanced bacterial adhesions only under low ionic strengths, but hindered their adhesion at higher ionic strengths. In addition, during the experiments using the components of P. aeruginosa PAO1 EPS, proteins seem to dominate the impact of EPS on bacterial adhesion. The extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was applied to explain the adhesion of P. aeruginosa PAO1 to solid surfaces.