title: Phosphorylcholine impairs susceptibility to biofilm formation of hydrogel contact lenses.
abstract: OBJECTIVE
  To compare silicone-hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), and phosphorylcholine-coated (PC-C) contact lenses in terms of their susceptibility to biofilm formation by Staphylococcus epidermidis and Pseudomonas aeruginosa.
  
  
  METHODS
  Laboratory investigation.
  
  
  METHODS
  Biofilm formation on colonized test lenses was evaluated with confocal microscopy and in vitro antibiotic susceptibility assays. The results of the latter assays were compared with those performed on planktonic cultures of the same organism.
  
  
  RESULTS
  For both microorganisms, sessile colonies on silicone-hydrogel and pHEMA lenses displayed lower antibiotic susceptibility than their planktonic counterparts. In contrast, the susceptibility of cultures growing on PC-C lenses was comparable with that for planktonic cultures. In particular, minimum inhibitory concentration for Tazocin (piperacillin plus tazobactam; Wyeth Pharmaceuticals, Aprilia, Italy; S. epidermidis) and gentamicin (P. aeruginosa) was identical, either in the presence of PC-C support or in planktonic cultures (Tazocin, </= 0.2 mug/ml; gentamicin, 0.4 mug/ml). Minimum inhibitory concentration for imipenem (P. aeruginosa) was two-fold higher for PC-C lenses (0.4 mug/ml) with respect to planktonic cultures (0.2 mug/ml). Confocal microscopy of lenses colonized for 24 hours with P. aeruginosa green fluorescent protein-expressing cells revealed a sessile colonization on silicone-hydrogel lens and a few isolated bacterial cells scattered widely over the surface of the PC-C lens.
  
  
  CONCLUSIONS
  An increase in antibiotic susceptibility of bacterial cultures was associated with diminished bacterial adhesion. Our results indicate that PC-C lenses seem to be more resistant than silicone-hydrogel and pHEMA lenses to bacterial adhesion and colonization. This feature may facilitate their disinfection.
authors.affiliation: Department of Public Health Sciences G. Sanarelli, La Sapienza University, Rome, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Selan
authors.forename: Stefano
authors.initials: S
authors.lastname: Palma
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Scoarughi
authors.forename: Rosanna
authors.initials: R
authors.lastname: Papa
authors.forename: Richard
authors.initials: R
authors.lastname: Veeh
authors.forename: Daniele
authors.initials: D
authors.lastname: Di Clemente
authors.forename: Marco
authors.initials: M
authors.lastname: Artini
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects*; D020099:Coated Materials, Biocompatible; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D005839:Gentamicins / Q000494:pharmacology; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D015378:Imipenem / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010767:Phosphorylcholine / Q000494:pharmacology*; D010878:Piperacillin / Q000494:pharmacology; D000077725:Piperacillin, Tazobactam Drug Combination; D011102:Polyhydroxyethyl Methacrylate; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000502:physiology*; D012825:Silicon; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000502:physiology*
chemical_list: D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D005839:Gentamicins; D010767:Phosphorylcholine; D000077725:Piperacillin, Tazobactam Drug Combination; D011102:Polyhydroxyethyl Methacrylate; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D015378:Imipenem; D010397:Penicillanic Acid; D010878:Piperacillin; D012825:Silicon