Physicochemical factors influencing bacterial transfer from contact lenses to surfaces with different roughness and wettability

Abstract

The aim of this study was to determine the transfer of Pseudomonas aeruginosa No. 3 and Staphylococcus aureus 835 from contact lenses to surfaces with different hydrophobicity and roughness. Bacteria were allowed to adhere to contact lenses (Surevue, PureVision, or Focus Night & Day) by incubating the lenses in a bacterial suspension for 30 min. The contaminated lenses were put on a glass, poly(methylmethacrylate), or silicone rubber substratum, shaped to mimic the eye. After 2 and 16 h, lenses were separated from the substrata and bacteria were swabbed off from the respective surfaces and resuspended in saline. Appropriate serial dilutions of these suspensions were made, from which aliquots were plated on agar for enumeration. Bacterial transfer varied between 4 and 60%, depending on the combination of strain, contact time, contact lens, and substratum surface. For P. aeruginosa No. 3, transfer was significantly higher after 16 h than after 2 h, whereas less increase with time was seen for S. aureus 835. Bacterial transfer from all tested contact lenses was least to silicone rubber, the most hydrophobic and roughest substratum surface included.

Silicone hydrogel contact lens surface analysis by atomic force microscopy: shape parameters

“…9 Thus, the roughness differences between lenses observed here cannot be attributed to the manufacturing procedure. Besides the mode of elaboration, other authors have linked the presence of methacrylic acid (MA) 6 or a reduced water content 24,9 to a greater lens surface roughness.…”

Hydrogel Contact Lenses Surface Roughness and Bacterial Adhesion

“…It was also previously demonstrated that the surface roughness increase, the biofilm deposited on the lens increase (Baguet et al, 1995), and that bacterial transfer from a CL is determined by the roughness and hydrophobicity of the surface receiving the bacteria (Vermeltfoort et al, 2004). Daily replacement CL in present study are suppose to acquire more deposits during wear as they had the highest increase in roughness values when higher areas are considered.…”

“…The effect of surface roughness on bacterial adhesion to a CL is still far from being well understood. According to prior work, it seems clear that surface roughness is related to deposit formation and microorganism colonization of the surface (Baguet et al, 1995;Vermeltfoort et al, 2004). Greater surface roughness determines a greater specific surface area, thus creating more available active sites for thermodynamic reactions.…”

“…Thus, the roughness differences between lenses cannot be attributed only to the manufacturing procedure. Besides the mode of elaboration, other authors have linked the presence of methacrylic acid (MA) (Baguet et al, 1993) or a reduced water content (Guryca et al, 2007;Vermeltfoort et al, 2004) to a greater lens surface roughness.…”

“…Surface roughness also need to be considered since deposits are more likely to form on imperfections of the lens surface (Hosaka et al, 1983). It was also previously demonstrated that as surface roughness increases, the biofilm deposited on the lens also increases (Baguet et al, 1995) and that bacterial transfer from a contact lens is determined by the roughness and hydrophobicity of the surface receiving the bacteria (Vermeltfoort et al, 2004).…”