title: Effect of cholesterol deposition on bacterial adhesion to contact lenses.
abstract: OBJECTIVE
  To examine the effect of cholesterol on the adhesion of bacteria to silicone hydrogel contact lenses.
  
  
  METHODS
  Contact lenses, collected from subjects wearing Acuvue Oasys or PureVision lenses, were extracted in chloroform:methanol (1:1, v/v) and amount of cholesterol was estimated by thin-layer chromatography. Unworn lenses were soaked in cholesterol, and the numbers of Pseudomonas aeruginosa strains or Staphylococcus aureus strains that adhered to the lenses were measured. Cholesterol was tested for effects on bacterial growth by incubating bacteria in medium containing cholesterol.
  
  
  RESULTS
  From ex vivo PureVision lenses, 3.4 ± 0.3 μg/lens cholesterol was recovered, and from Acuvue Oasys lenses, 2.4 ± 0.2 to 1.0 ± 0.1 μg/lens cholesterol was extracted. Cholesterol did not alter the total or viable adhesion of any strain of P. aeruginosa or S. aureus (p > 0.05). However, worn PureVision lenses reduced the numbers of viable cells of P. aeruginosa (5.8 ± 0.4 log units) compared with unworn lenses (6.4 ± 0.2 log units, p = 0.001). Similarly, there were fewer numbers of S. aureus 031 adherent to worn PureVision (3.05 ± 0.8 log units) compared with unworn PureVision (4.6 ± 0.3 log units, p = 0.0001). Worn Acuvue Oasys lenses did not affect bacterial adhesion. Cholesterol showed no effect on the growth of any test strain.
  
  
  CONCLUSIONS
  Although cholesterol has been shown to adsorb to contact lenses during wear, this lipid does not appear to modulate bacterial adhesion to a lens surface.
authors.affiliation: Brien Holden Vision Institute, Level 5, North Wing, RMB, Gate 14, Barker Street, University of New South Wales, Sydney 2052, NSW Australia. n.babaei@brienholdenvision.org
authors.forename: Negar
authors.initials: N
authors.lastname: Babaei Omali
authors.forename: Hua
authors.initials: H
authors.lastname: Zhu
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Zhao
authors.forename: Jerome
authors.initials: J
authors.lastname: Ozkan
authors.forename: Banglao
authors.initials: B
authors.lastname: Xu
authors.forename: Roya
authors.initials: R
authors.lastname: Borazjani
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
mesh_terms: D000042:Absorption; D001422:Bacterial Adhesion / Q000187:drug effects*; D002784:Cholesterol / Q000494:pharmacology*; D002855:Chromatography, Thin Layer; D015169:Colony Count, Microbial; D003262:Contact Lenses, Extended-Wear / Q000382:microbiology*; D018592:Cross-Over Studies; D006801:Humans; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000254:growth & development*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development*
chemical_list: D002784:Cholesterol