Association of Pseudomonas aeruginosa and Serratia marcescens with extended-wear soft contact lenses in asymptomatic patients.

PURPOSE: To isolate and identify aerobic bacteria, particularly gram-negative species associated with the use of extended-wear (EW) soft contact lenses. METHODS: Extended-wear contact lenses were collected, using aseptic technique, from the eyes of individuals after 30 days of extended wear (5-7 day intermittent periods) and were examined for adhered aerobic bacteria. RESULT: Coagulase-negative staphylococci (CoNS) were isolated from 74% of the lenses. Serratia marcescens was found at an incidence of 10% and Pseudomonas aeruginosa at an incidence of 6%. CONCLUSION: The presence of species of bacteria, including P. aeruginosa and S. marcescens, that have been associated with daily wear soft contact lenses, solutions, and cases also appear to be associated with EW lenses.