title: Antimicrobial in vitro evaluation of corneal storage media using a closed chamber study model.
abstract: OBJECTIVE
  To evaluate in vitro the antimicrobial influence of the corneal storage media containing antibiotics using a closed chamber study model under the closest simulated environment of corneal preservation process.
  
  
  METHODS
  Samples of cornea storage media containing streptomycin and gentamicin (Optisol-GS) were analyzed at different moments after its contamination with Staphylococcus aureus (ATCC25923). Samples were analyzed at 1, 2, 3, 4, 5, 6, 24, 48, 72 hours; 7 days; and 14 days after contamination. The samples were analyzed using a new study model system that consists of two closed coupled chambers. The upper chamber contained two culture media (chocolate agar and Sabouraud agar) and CO(2) indicator (indication of bacterial aerobic activity). The inferior chamber contained supplemented solution with an antimicrobial inhibitor. The bacterial growth parameters were analyzed by the presence or absence of bacteria in chocolate agar and by color change of CO(2) indicator when positive. First reading was performed after 24 hours, and, in the absence of bacterial growth, a second reading was carried out after 48 hours.
  
  
  RESULTS
  Color change in CO(2) indicator was found in samples contaminated after 1, 2, and 3 hours on the first reading. On the second reading, we observed color change in all remaining samples, except for samples contaminated after 14 days.
  
  
  CONCLUSIONS
  Samples of cornea storage media containing gentamicin sulphate and streptomycin sulphate in vitro showed viable Staphylococcus aureus for up to 7 days of contamination.
authors.affiliation: Department of Ophthalmology, Santa Casa de Sao Paulo, Brazil.
authors.forename: Davi Chen
authors.initials: DC
authors.lastname: Wu
authors.forename: Lycia Mara Jenne
authors.initials: LM
authors.lastname: Mimica
authors.forename: Cely Barreto
authors.initials: CB
authors.lastname: Silva
authors.forename: Suely Mitio Ykko
authors.initials: SM
authors.lastname: Ueda
authors.forename: Richard Yudi
authors.initials: RY
authors.lastname: Hida
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002809:Chondroitin Sulfates / Q000494:pharmacology*; D015169:Colony Count, Microbial; D045424:Complex Mixtures / Q000494:pharmacology; D003315:Cornea; D015925:Cryopreservation; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D003911:Dextrans / Q000494:pharmacology*; D004338:Drug Combinations; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D008954:Models, Biological; D009926:Organ Preservation; D019188:Organ Preservation Solutions / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development; D013307:Streptomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D045424:Complex Mixtures; D016895:Culture Media, Serum-Free; D003911:Dextrans; D004338:Drug Combinations; D005839:Gentamicins; D019188:Organ Preservation Solutions; D002809:Chondroitin Sulfates; C075736:Optisol; D013307:Streptomycin