Pseudomonas attachment to new hydrogel contact lenses.

The adhesion of two strains of Pseudomonas aeruginosa to unworn hydrogel contact lenses (CLs) was studied by scanning electron microscopy. New daily-wear polymacon lenses (38.6% water content) and extended-wear lidofilcon A lenses (70% water content) were exposed to a suspension of 10(8) colony-forming units per milliliter of P aeruginosa for 2, 5, 15, 30, and 60 minutes. Increasing numbers of bacteria were found to attach to the lenses with time, and no significant differences between CL types were demonstrated. Attachment was considered to be irreversible since washing did not remove the bacteria. We conclude that P aeruginosa can actively attach to new, unworn hydrogel CLs.