title: Increased resistance of contact lens-related bacterial biofilms to antimicrobial activity of soft contact lens care solutions.
abstract: OBJECTIVE
  To determine if clinical and reference strains of Pseudomonas aeruginosa, Serratia marcescens, and Staphylococcus aureus form biofilms on silicone hydrogel contact lenses and ascertain antimicrobial activities of contact lens care solutions.
  
  
  METHODS
  Clinical and American Type Culture Collection reference strains of P. aeruginosa, S. marcescens, and S. aureus were incubated with lotrafilcon A lenses under conditions that facilitate biofilm formation. Biofilms were quantified by quantitative culturing (colony-forming units, CFUs), and gross morphology and architecture were evaluated using scanning electron microscopy and confocal microscopy. Susceptibilities of the planktonic and biofilm growth phases of the bacteria to 5 common multipurpose contact lens care solutions and 1 hydrogen peroxide care solution were assessed.
  
  
  RESULTS
  Pseudomonas aeruginosa, S. marcescens, and S. aureus reference and clinical strains formed biofilms on lotrafilcon A silicone hydrogel contact lenses, as dense networks of cells arranged in multiple layers with visible extracellular matrix. The biofilms were resistant to commonly used biguanide-preserved multipurpose care solutions. Pseudomonas aeruginosa and S. aureus biofilms were susceptible to a hydrogen peroxide and a polyquaternium-preserved care solution, whereas S. marcescens biofilm was resistant to a polyquaternium-preserved care solution but susceptible to hydrogen peroxide disinfection. In contrast, the planktonic forms were always susceptible.
  
  
  CONCLUSIONS
  Pseudomonas aeruginosa, S. marcescens, and S. aureus form biofilms on lotrafilcon A contact lenses, which in contrast to planktonic cells are resistant to the antimicrobial activity of several soft contact lens care products.
authors: Department of Ophthalmology and Visual Sciences, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH 44106, USA.
authors: Loretta B
authors: LB
authors: Szczotka-Flynn
authors: Yoshifumi
authors: Y
authors: Imamura
authors: Jyotsna
authors: J
authors: Chandra
authors: Changping
authors: C
authors: Yu
authors: Pranab K
authors: PK
authors: Mukherjee
authors: Eric
authors: E
authors: Pearlman
authors: Mahmoud A
authors: MA
authors: Ghannoum
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000592:standards; D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D018639:Contact Lens Solutions / Q000494:pharmacology* / Q000592:standards; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020100:Hydrogels; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010933:Plankton / Q000187:drug effects / Q000502:physiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000502:physiology; D012706:Serratia marcescens / Q000187:drug effects / Q000502:physiology; D012828:Silicones; D013211:Staphylococcus aureus / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D005466:Fluorocarbons
chemical_list: D000900:Anti-Bacterial Agents; D018639:Contact Lens Solutions; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020100:Hydrogels; D012828:Silicones; C481129:lotrafilcon A; D005466:Fluorocarbons