Effects of multipurpose contact-lens care solutions on adhesion of pseudomonas aeruginosa to corneal epithelial cells

PURPOSE:: To study the adhesion of Pseudomonas aeruginosa (PA) to human corneal epithelial cells treated with multipurpose contact-lens care solutions (MPSs). METHODS:: SV40-immortalized human corneal epithelial cells (svHCET cells) were cultured on collagen-coated culture slides for 7 days. The svHCET cells were exposed to three MPSs: MPS-A (polyhexamethylene biguanide, macrogolglycerol hydroxystearate), MPS-B (polyhexamethylene biguanide, Poloxamer, and boric acid) or MPS-C (Polyquad, Poloxamine, and boric acid) for 60 min. PA cells (ATCC27853) were inoculated onto cultured svHCET cells and adhesion was observed with a PKH67 fluorescent dye-labeling method using a confocal laser scanning microscope. The number of adherent PA was assessed by 16S-rDNA quantification using real-time polymerase chain reaction and confocal laser scanning microscope imaging. PA adhesion and inter- and intracellular invasion into svHCET cells were also observed with scanning electron microscopy and transmission electron microscopy. RESULTS:: PA adhesion was more than three times higher in MPS-B-treated cells and six times higher in MPS-C-treated cells compared with control estimated by real-time polymerase chain reaction (P < 0.05). MPS-A-treated cells showed no significant increase in PA adhesion. With scanning electron microscopy and transmission electron microscopy, PA were observed to enter opened cell-cell borders between adjacent svHCET cells treated with MPS-B and C, but not with MPS-A. CONCLUSIONS:: Taken together, these results support the possibility that chronic use of MPS containing boric acid (MPS-B and MPS-C) by hydrogel contact lens wearers may lead to increased risk for associated microbial corneal infection with PA.