ORIGINAL ARTICLE The Effect of Octylglucoside and Sodium Cholate in Staphylococcus epidermidis and Pseudomonas aeruginosa Adhesion to Soft Contact Lenses Lı ´VIA SANTOS, MSc, DIANA RODRIGUES, BSc, MADALENA LIRA, MSc, ROSA ´ RIO OLIVEIRA, PhD, M. ELISABETE C. D. REAL OLIVEIRA, PhD, EVA YEBRA-PIMENTEL VILAR, PhD, and JOANA AZEREDO, PhD Instituto de Biotecnologia e Bioengenharia, Centro de Engenharia Biolo ´gica, Universidade do Minho, Minho, Portugal (LS, DR, RO, JA), Centro de Fı ´sica, Universidade do Minho, Minho, Portugal (ML, MECDRO), and Departamento de O ´ ptica e Optometria, Universidade de Santiago de Compostela, Spain (EY-PV) ABSTRACT Purpose. In this study, the effect of the natural surfactants octylglucoside and sodium cholate in inhibiting Staphylococcus epidermidis and Pseudomonas aeruginosa adhesion to conventional and silicone-hydrogel contact lenses (CL) was assessed. Hydrophobicity was also evaluated to conditioned and nonconditioned CL. Methods. The inhibiting effect of the tested surfactants was determined through “in vitro” adhesion studies to conditioned and nonconditioned CL followed by image acquisition and cell enumeration. Hydrophobicity was evaluated through contact angle measurements using the advancing type technique on air. Results. Sodium cholate exhibits a very low capability to inhibit microbial adhesion. Conversely, octylglucoside effectively inhibited microbial adhesion in both types of lenses. This surfactant exhibited an even greater performance than a multipurpose lens care solution used as control. Octylglucoside was the only tested surfactant able to lower the hydrophobicity of all CL, which can explain its high performance. Conclusions. The results obtained in this study point out the potential of octylglucoside as a conditioning agent to prevent microbial colonization. (Optom Vis Sci 2007;84:429–434) Key Words: octylglucoside, sodium cholate, Staphylococcus epidermidis, Pseudomonas aeruginosa, inhibition of adhesion O ver the last few decades the number of contact lens (CL) wearers has grown rapidly because of the esthetic, ther- apeutic, visual, and comfort reasons. There are several kinds of lenses commercially available. However, soft CL are the most common. These lenses are composed of hydrophilic mono- mers such as hydroxyethylmethacrylate, N-vynil pyrrolidone, methacrylic acid, and polyvinyl alcohol. 1,2 Recently, the introduction of silicone-containing hydrogel CL having the same comfort and sig- nificantly higher oxygen permeability than conventional-hydrogel has resulted in a new generation of soft CL. The high oxygen permeability, on account of the siloxane component, makes it possible to wear these lenses on a continuous basis for 30 days. 1–3 The occurrence of CL associated keratitis as well as other ocular complications has been a target of continuous research in several fields. When a CL is placed in the eye, the lachrymal tear compo- nents are adsorbed on its surface, building an organic substrate for subsequent microbial adhesion. 4 In particular, when the corneal tissues are no longer intact due to hypoxic conditions or mechan- ical friction, microbes can invade the cornea and induce an ocular infection. 4,5 So, the development of strategies such as the improve- ment of lens materials and lens care systems that avoid or decrease CL associated infections are very important aspects of soft CL research. The incorporation of surfactants in the lens care systems is useful not only to solubilize the organic tear film components 1040-5488/07/8405-0429/0 VOL. 84, NO. 5, PP. 429–434 OPTOMETRY AND VISION SCIENCE Copyright © 2007 American Academy of Optometry Optometry and Vision Science, Vol. 84, No. 5, May 2007