title: Efficacy of multipurpose contact lens solutions against ESBL-positive Escherichia coli, MRSA, and Candida albicans clinical isolates.
abstract: OBJECTIVE
  The antimicrobial effects of multipurpose contact lens solutions (MPSs) have been evaluated according to ISO 14729 standards. The aim of this study was to assess the efficacy of commercially available MPSs against extended-spectrum beta lactamases (ESBL)-producing Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans clinical isolates.
  
  
  METHODS
  Three commercially available contact lens solutions (Opti-Free Expresss, ReNu MultiPlus, and Solo Care Aqua) were tested against 18 ESBL-positive E. coli clinical strains, 20 MRSA clinical strains, and 20 C. albicans clinical strains. The stand-alone assays for bacteria and fungi were performed according to ISO 14729 criteria, and all samples were evaluated after 2, 4, and 24 hours of incubation. The numbers of viable microorganisms were evaluated by the plate-counting method.
  
  
  RESULTS
  All MPSs demonstrated at least 3 log reduction in colony-forming units (CFU) for all bacterial isolates and 1 log reduction in CFU for all yeast isolates, which meets ISO 14729 standards. Although no statistically significant differences were obtained among MPSs for bacterial isolates, variable responses were observed against clinical isolates: 5% povidone-iodine was more effective compared with Solo Care Aqua for C. albicans clinical strains (P<0.05); and all solutions were effective after an incubation time of only 2 hrs. The MPSs showed good activity against S. aureus, E. coli, and C. albicans.
  
  
  CONCLUSIONS
  Although effective log reductions were provided with all MPSs, the reduction was variable depending on the strains tested. Multipurpose contact lens solutions should be tested under ISO 14729 standards for both standard and clinical strains.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, Baskent University, Ankara, Turkey.
authors.forename: Muge
authors.initials: M
authors.lastname: Demirbilek
authors.forename: Ebru
authors.initials: E
authors.lastname: Evren
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects*; D015169:Colony Count, Microbial; D018639:Contact Lens Solutions / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods; D004926:Escherichia coli / Q000187:drug effects*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests
chemical_list: D000890:Anti-Infective Agents; D018639:Contact Lens Solutions