Abstract
Purpose. The tear cationic protein lactoferrin increases the activity of various antimicrobial agents against suspended bacterial cultures including Staphylococcus epidermidis, the predominant causative agent of intraocular lens biofilm infections. We investigated the ability of lactoferrin to enhance the activity of vancomycin and lysozyme against biofilms of a clinical S. epidermidis isolate. Methods. Biofilms were prepared on soft contact lenses and cells released from the biofilm surface were collected from the surrounding broth. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against the intact biofilm, released cells and suspended bacteria were evaluated using vancomycin with and without lactoferrin. Results. Lactoferrin induced a two-fold reduction in the MBC of vancomycin for biofilm (p < 0.01) and biofilm-released cells from 64 µg/ml to 32 µg/ml and similarly decreased the MIC for biofilm-released cells (p < 0.01) from 32 µg/ml to 16 µg/ml. With or wi...