Adhesion of Pseudomonas aeruginosa and Staphylococcus epidermidis to Silicone???Hydrogel Contact Lenses

Abstract

As a result of their hydrophobicity, the extended wear silicone-hydrogel lenses (lotrafilcon A and balafilcon A) may carry higher risk of microbial contamination than both the hydrophilic daily wear silicone-hydrogel lens, galyfilcon A and the conventional hydrogel lens, etafilcon A.

Hydrogel Contact Lenses Surface Roughness and Bacterial Adhesion

“…Although this is consistent with other studies for other bacterial strains (Borazjani et al, 2004;Santos et al, 2008), it challenges the established relationship between microbial adhesion and lens surface hydrophobicity (Pritchard et al, 1999;Doyle, 2000;Young et al, 2002;van Oss, 2003;Giraldez et al, 2010b). This discrepancy could be explained by the different extents of microbial colonization observed for different bacterial strains, and/or the different methodologies employed (Henriques et al, 2005;Kodjikian et al, 2007). In fact, most P. aeruginosa strains have a more hydrophilic surface than S. epidermidis or other bacteria (Gottenbos et al, 2001;MitikDineva et al, 2009).…”

“…Notwithstanding, Santos et al were unable to detect any difference in microbial adhesion when comparing unworn silicone hydrogel and conventional hydrogel CL. This discrepancy could be explained by the different extents of microbial colonization observed for different S. epidermidis strains, and/or the different methodologies employed (Henriques et al, 2005;Kodjikian et al, 2007). In both hydrophobic and hydrophilic groups, the lenses showing the lowest Ra values (omafilcon A and comfilcon A) also returned the lowest numbers of S. epidermidis CFU, despite their high Rku and Rsk values.…”

“…Initial adhesion of S. epidermidis to unworn or worn conventional hydrogel CL has been reported to be strain and substrate related, the hydrophilic nature of the lens being a key factor (George et al, 2003;Henriques et al, 2005). The incorporation of silicone in a hydrogel polymer achieves high oxygen permeability but on the other hand reduces hydrophilicity (Tighe B, 2009).…”

Prevalence of Biofilm Formation and Wide Distribution of Virulence Associated Genes among Vibrio spp. Strains Isolated from the Monastir Lagoon, Tunisia

“…At the end of the experiment, each well was washed twice with PBS to remove non-adherent or loosely adherent bacteria. After the last wash the pieces were removed from each well and immersed in a new microtiter plate with 1 ml of 98% (w/v) methanol in each well (Henriques et al, 2005). The methanol was discarded after 15 min of contact and the pieces were allowed to dry at room temperature.…”

Diversity of heterotrophic bacteria isolated from biofilm samples and cell surface hydrophobicity

“…The hydrophobicity values of these isolates were not affected by the culture conditions, such as the culture medium and temperature, and no marked tendency was noted. Pseudomonas aeruginosa and Staphylococcus epidermidis are generally known to be very adhesive (Henriques et al, 2005), but it was clarifi ed that minor bacterial species with a hydrophobic cell surface layer, such as those isolated, were present. Adhesion is essential to many microorganisms, and adhesion to carriers may be signifi cant for biofi lm formation.…”