Antibiotics in the irrigating solutions reduce Staphylococcus epidermidis adherence to intraocular lenses

Purpose To investigate the effect of antibiotics in the irrigating solution s on hydrophobicity, slime production and the adherence of Staphylococcus e pidermidis to intraocular lenses (IOLs). Methods A standard culture of S. epidermidis was incubated with a control p hosphate-buffered saline (PBS) or PBS containing vancomycin (20 mu g/ml) or gentamicin (8 mu g/ml) or a combination of gentamicin and vancomycin (8 an d 20 mu g/ml, respectively) for 30, 60 and 120 min at 35 degrees C. The bac teria were harvested by centrifugation, and washed with PBS before incubati on with IOLs for 1 h. Adhesion of bacterial cells to IOLs was determined by counting the viable cells attached to the lenses. Slime production on IOLs was measured using safranin staining. Hydrophobicity of the control cultur es and cultures treated with antibiotics was assayed on the basis of the he xadecane droplet method. Results Bacterial exposure to antibiotics produced a time-dependent signifi cant decrease in bacterial hydrophobicity and adherence to IOLs compared wi th the untreated control cells (p < 0.001). Hydrophobicity showed a signifi cant correlation with adherence (r = 0.89, p < 0.001). Gentamicin was signi ficantly more effective than vancomycin, and the synergistic combination of gentamicin and vancomycin was the most effective in reducing bacterial adh erence to IOLs, hydrophobicity and slime production. Conclusions The use of antibiotics in the irrigating solutions during catar act surgery may be useful in reducing bacterial adherence to IOLs. Further studies are needed to determine the clinical implications of these findings in reducing the incidence of postoperative endophthalmitis associated with IOL implantation.