title: Bacterial and fungal biofilm formation on contact lenses and their susceptibility to lens care solutions.
abstract: BACKGROUND
  Microbial biofilm formation on contact lenses and lens storage cases may be a risk factor for contact lens-associated corneal infections. Various types of contact lens care solutions are used to reduce microbial growths on lenses.
  
  
  OBJECTIVE
  The present study aimed at comparing the growths of biofilms on the different contact lenses and lens cases. The study also aimed at determining the effect of lens care solutions and bacteriophage on these biofilms.
  
  
  METHODS
  One type of hard lens and two types of soft lenses were used for the study. The organisms used were Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 60193 and Escherichia coli ATCC 25922. Biofilm production was performed by modified O'Toole and Kolter method and effect of lens cleaning solutions and a crude coliphage on biofilms was also studied. Results were visualised using scanning electron microscopy and quantitated by colony counting method and spectrophotometric measurement of optical density (OD). Statistical analysis was done by SPSS 11.5, Kruskal-Wallis test and Chi-square test.
  
  
  RESULTS
  Soft lens cleaning solutions had a significant inhibitory effect (P = 0.020) on biofilm formation on soft lenses and also lens cases (P < 0.001). Soft lens cleaning solution 2 was more efficient than solution 1. However, no such inhibitory effect was observed with regard to hard lens cleaning solution, but for a significant reduction in the OD values (P < 0.001). There was no significant inhibitory effect by bacteriophages.
  
  
  CONCLUSIONS
  This study showed the importance of selecting the appropriate lens cleaning solution to prevent biofilm production on contact lenses.
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Kackar
authors.affiliation: Department of Microbiology, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: Ethel
authors.initials: E
authors.lastname: Suman
authors.affiliation: Department of Community Medicine, Kasturba Medical College, Manipal University, Mangalore, Karnataka, India.
authors.forename: M Shashidhar
authors.initials: MS
authors.lastname: Kotian
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000821:virology; D001433:Bacteriolysis; D018441:Biofilms / Q000254:growth & development*; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology; D003090:Coliphages / Q000254:growth & development; D015169:Colony Count, Microbial; D018639:Contact Lens Solutions / Q000494:pharmacology*; D003261:Contact Lenses / Q000382:microbiology*; D008855:Microscopy, Electron, Scanning; D013053:Spectrophotometry
chemical_list: D000890:Anti-Infective Agents; D018639:Contact Lens Solutions