title: Bacterial adhesion forces to Ag-impregnated contact lens cases and transmission to contact lenses.
abstract: OBJECTIVE
  To measure adhesion forces of Pseudomonas aeruginosa, Staphylococcus aureus, and Serratia marcescens to a rigid contact lens (CL), standard polypropylene, and Ag-impregnated lens cases using atomic force microscopy and determine bacterial transmission from lens case to CL.
  
  
  METHODS
  Adhesion forces of bacterial strains to Ag-impregnated and polypropylene lens cases and a rigid CL were measured using atomic force microscopy. Adhesion forces were used to calculate Weibull distributions, from which transmission probabilities from lens case to CL were derived. Transmission probabilities were compared with actual transmission of viable bacteria from a lens case to the CL in 0.9% NaCl and in an antimicrobial lens care solution.
  
  
  RESULTS
  Bacterial transmission probabilities from polypropylene lens cases based on force analysis coincided well for all strains with actual transmission in 0.9% NaCl. Bacterial adhesion forces on Ag-impregnated lens cases were much smaller than that on polypropylene and CLs, yielding a high probability of transmission. Comparison with actual bacterial transmission indicated bacterial killing due to Ag ions during colony-forming unit transmission from an Ag-impregnated lens case, especially for P. aeruginosa. Transmission of viable bacteria from Ag-impregnated lens cases could be further decreased by use of an antimicrobial lens care solution instead of 0.9% NaCl.
  
  
  CONCLUSIONS
  Bacterial transmission probabilities are higher from Ag-impregnated lens cases than from polypropylene lens cases because of small adhesion forces, but this is compensated for by enhanced bacterial killing due to Ag impregnation, especially when in combination with an antimicrobial lens care solution. This calls for a balanced combination of antimicrobial lens care solutions and surface properties of a lens case and CL.
authors.affiliation: Department of Biomedical Engineering, W.J. Kolff Institute, University Medical Center Groningen and University of Groningen, Groningen, The Netherlands.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Qu
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
authors.forename: Johanna M M
authors.initials: JM
authors.lastname: Hooymans
mesh_terms: D000890:Anti-Infective Agents; D001422:Bacterial Adhesion / Q000502:physiology*; D018407:Bacterial Physiological Phenomena; D020099:Coated Materials, Biocompatible; D015169:Colony Count, Microbial; D003261:Contact Lenses / Q000382:microbiology*; D004866:Equipment Contamination / Q000517:prevention & control; D018625:Microscopy, Atomic Force; D011126:Polypropylenes; D019064:Product Packaging / Q000295:instrumentation*; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000502:physiology; D012706:Serratia marcescens / Q000302:isolation & purification / Q000502:physiology; D018030:Silver Compounds; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000502:physiology; D013499:Surface Properties
chemical_list: D000890:Anti-Infective Agents; D020099:Coated Materials, Biocompatible; D011126:Polypropylenes; D018030:Silver Compounds