Adhesion of Pseudomonas aeruginosa to contact lenses after exposure to multi-purpose lens care solutions

Elemental surface compositions of contact lenses were measured after exposure to different lens care solutions (LCS) using X-ray photoelectron spectroscopy and were related to adhesion and detachment of Pseudomonas aeruginosa. Etafilcon A and polymacon contact lenses, prior to and after exposure to LCS were fixed on the bottom plate of a parallel plate flow chamber after which P. aeruginosa #3 was allowed to adhere for 2 h. After adhesion, bacterial detachment was stimulated by perfusing the chamber with an LCS or by passing an air-bubble through the chamber. After exposure to an LCS, the adhesion of P. aeruginosa #3 could either be enhanced or decreased, depending on the contact lens and LCS involved. Initial deposition rates of P aeruginosa #3 could not be related with changes in elemental surface composition of the contact lenses, but decreased with an increasing ratio of oxygen involved in O=C bonds relative to oxygen in O-C bonds. P. aeruginosa #3 adhered tenaciously to both types of contact lenses and the passage of an air-bubble through the flow chamber detached only up to 9% of the adhering bacteria. Alternatively, the LCS most effective in decreasing bacterial adhesion after exposure (LCS A), was least effective in detaching adhering R aeruginosa #3 (8-15%), while the other LCS detached up to 42% of adhering bacteria. In conclusion, different LCS have different abilities to detach the adhering P aeruginosa #3 from contact lens surfaces and all leave adsorbed components on the surface after soaking. Adsorbed components rich in O-C bonds increased adhesion of P. aeruginosa #3 under the conditions used in this study and should, therefore, be avoided.