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

Elemental surface compositions of contact lenses were measured after exposu re to different lens care solutions (LCS) using X-ray photoelectron spectro scopy 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 w hich P. aeruginosa #3 was allowed to adhere for 2 h. After adhesion, bacter ial detachment was stimulated by perfusing the chamber with an LCS or by pa ssing an air-bubble through the chamber. After exposure to an LCS, the adhe sion of P. aeruginosa #3 could either be enhanced or decreased, depending o n the contact lens and LCS involved. Initial deposition rates of P aerugino sa #3 could not be related with changes in elemental surface composition of the contact lenses, but decreased with an increasing ratio of oxygen invol ved 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-bubbl e through the flow chamber detached only up to 9% of the adhering bacteria. Alternatively, the LCS most effective in decreasing bacterial adhesion aft er 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. I n conclusion, different LCS have different abilities to detach the adhering P aeruginosa #3 from contact lens surfaces and all leave adsorbed componen ts on the surface after soaking. Adsorbed components rich in O-C bonds incr eased adhesion of P. aeruginosa #3 under the conditions used in this study and should, therefore, be avoided.