A NEW MODEL TO ASSESS STAPHYLOCOCCAL ADHESION TO INTRAOCULAR LENSES UNDER IN-VITRO FLOW CONDITIONS

Adhesion of staphylococcal cells to intraocular lenses coated with hep arin was studied under in vitro flow conditions (280 mu l min(-1)) at 37 degrees C, The intraocular lenses were incubated with human cerebro spinal fluid for Ih or with cerebrospinal fluid including 0.50% plasma for 12 h, prior to bacterial challenge. Two strains of Staphylococcus epidermidis selected for this study, were isolated from biomaterial-a ssociated infections. Bacterial adhesion was quantitated by biolumines cence and visualized by fluorescence microscopy of acridine orange sta ined bacteria. Surface coating with heparin significantly decreased ba cterial adhesion of both strains after incubation with cerebrospinal f luid including 0.50% plasma for 12 h (p = 0.0209). However, no differe nce in bacterial adhesion was obtained between intraocular lenses with and without heparin, after incubation with cerebrospinal fluid for Ih (p = 0.327), Microscopy showed that more bacteria were present on int raocular lenses without heparin than on intraocular lenses with hepari n, The results show that preincubation with a proteinaceous fluid infl uences subsequent bacterial adhesion to the polymer surface. The resul ts suggest that IOLs with heparin coating may be less prone to bacteri al adhesion under perfusion conditions after surface conditioning in h uman CSF with 0.50% plasma and a preincubation period of 12 h. Heparin coating might be a valuable tool to decrease implant-associated bacte rial endophthalmitis. (C) 1998 Published by Elsevier Science Ltd, All rights reserved.