title: In vitro deposition of lysozyme on etafilcon A and balafilcon A hydrogel contact lenses: effects on adhesion and survival of Pseudomonas aeruginosa and Staphylococcus aureus.
abstract: OBJECTIVE
  To compare lysozyme adsorption and absorption and bacterial adhesion interactions on conventional (etafilcon A) and silicone (balafilcon A) hydrogel contact lenses.
  
  
  METHODS
  Lysozyme concentrations and activities associated with the lenses were determined after solvent extraction (trifluoroacetic acid/acetonitrile) and directly on the lenses without extraction with micrococcal- and micro-bicinchoninic acid (BCA) assays. Cells of bacteria with radiolabeled leucine and a cell recovery procedure were used in determinations of bacterial adhesion to lenses.
  
  
  RESULTS
  Lysozyme was adsorbed and absorbed to the conventional etafilcon A lens at about a 10-fold greater concentration than to the balafilcon A silicone hydrogel lens. Enzyme activities on the surfaces of both lenses were similar but replenished after saline extraction only with the etafilcon A lens. Lysozyme on the lens surface showed significant lysis of Micrococcus luteus but had a negligible effect on the adhesion and survival of Staphylococcus aureus. Lysozyme did not appear to affect the survival of Pseudomonas aeruginosa on lenses.
  
  
  CONCLUSIONS
  In vitro experiments show that concentrations of active lysozyme on the surface of the etafilcon A lens, unlike the balafilcon A lens which showed negligible absorption, may be sustained from the lens matrix. Lysozyme deposited on hydrogel lenses had marked activity against M. luteus but relatively minor effects on the primary adhesion of P. aeruginosa and S. aureus.
authors.affiliation: Biology Department, Georgia State University, Kell Hall, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA. zhangshangtong@yahoo.com
authors.forename: Shangtong
authors.initials: S
authors.lastname: Zhang
authors.forename: Roya N
authors.initials: RN
authors.lastname: Borazjani
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Salamone
authors.forename: Donald G
authors.initials: DG
authors.lastname: Ahearn
authors.forename: Sidney A
authors.initials: SA
authors.lastname: Crow
authors.forename: George E
authors.initials: GE
authors.lastname: Pierce
mesh_terms: D000327:Adsorption; D001422:Bacterial Adhesion; D015169:Colony Count, Microbial; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D066298:In Vitro Techniques; D008689:Methacrylates; D009113:Muramidase / Q000378:metabolism*; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D012826:Silicone Elastomers; D013211:Staphylococcus aureus / Q000502:physiology*
chemical_list: D008689:Methacrylates; D012826:Silicone Elastomers; C114176:etafilcon; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D009113:Muramidase