Bacterial colonization of rigid gas permeable and hydrogel contact lenses by Staphylococcus aureus

Staphylococcus aureus ATCC 6538 and a clinical isolate of S. aureus from a bacterial keratitis patient were examined for their ability to adhere to et afilcon A, polymacon, silafocon, and pauflufocon A, B and C contact lenses. Both isolates adhered more to the rigid gas permeable (RGP) materials than to the hydrogel lenses tested (P < 0.05), S. aureus ATCC 6538 adhered to t he etafilcon A material to a greater extent than did the clinical isolate ( P < 0.05). There were no statistically significant differences in the recov ery of staphylococci from unworn lens materials when surface area, composit ion and ionicity were evaluated for either the hydrogel or RGP lenses teste d against lenses of a similar type. However, differences were observed when hydrogel lenses were evaluated against RGP tenses (P < 0.05). These differ ences may be related to water content.