title: Bacteria Colonizing the Ocular Surface in Eyes With Boston Type 1 Keratoprosthesis: Analysis of Biofilm-Forming Capability and Vancomycin Tolerance.
abstract: OBJECTIVE
  To analyze the bacterial microbiota colonizing the ocular surface of patients with Boston type 1 keratoprostheses (K-Pros) for antibacterial resistance patterns and capacity to form biofilms.
  
  
  METHODS
  Twenty-seven eyes with a Boston type 1 K-Pro and 16 fellow control eyes from 26 patients were enrolled. The surface of the K-Pro optic and/or the inferior conjunctival fornix was swabbed and plated separately on culture media. Positive cultures were processed to assess for biofilm-forming capability. Microtiter plate adherence assay and polymerase chain reaction for ica and atlE genes were used. An in vitro assay of vancomycin tolerance was performed on isolated strains and compared to standard controls with and without biofilm-forming capability.
  
  
  RESULTS
  Eighty-five percent of K-Pro eyes and 69% of control eyes had positive cultures (P = 0.20). All Gram-positive strains exhibited susceptibility to vancomycin by standard testing. Biofilm-forming bacterial isolates were detected in 57.7% of K-Pro eyes and 53.3% of control eyes. A vancomycin tolerance assay showed that the antibiotic susceptibility of coagulase-negative staphylococcus (CNS) within biofilms was significant in only three of five biofilm-forming strains (P < 0.05). In all strains, bacterial cells in planktonic form were more susceptible to vancomycin than in biofilm form (P < 0.001).
  
  
  CONCLUSIONS
  Coagulase-negative staphylococcus can be isolated from K-Pro surfaces despite the use of vancomycin prophylaxis. In this study, the majority of isolated strains had biofilm-forming capability. In vitro vancomycin tolerance assays suggest that biofilm formation decreases susceptibility to vancomycin. This may contribute to higher rates of infectious complications observed in these patients.
authors.affiliation: Department of Ophthalmology and Visual Sciences University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Sarmad H
authors.initials: SH
authors.lastname: Jassim
authors.affiliation: Department of Ophthalmology and Visual Sciences University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Kavitha R
authors.initials: KR
authors.lastname: Sivaraman
authors.affiliation: Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Juan Cristobal
authors.initials: JC
authors.lastname: Jimenez
authors.affiliation: Department of Ophthalmology and Visual Sciences University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Assraa H J
authors.initials: AH
authors.lastname: Jaboori
authors.affiliation: Department of Medicinal Chemistry and Pharmacology, Center for Pharmaceutical Biotechnology, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Federle
authors.affiliation: Department of Ophthalmology and Visual Sciences University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Jose
authors.initials: J
authors.lastname: de la Cruz
authors.affiliation: Department of Ophthalmology and Visual Sciences University of Illinois at Chicago, Chicago, Illinois, United States.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Cortina
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects / Q000235:genetics; D018441:Biofilms / Q000187:drug effects*; D016022:Case-Control Studies; D015169:Colony Count, Microbial; D003315:Cornea / Q000382:microbiology / Q000648:ultrastructure; D003316:Corneal Diseases / Q000601:surgery; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial; D015818:Eye Infections, Bacterial / Q000188:drug therapy / Q000382:microbiology*; D005798:Genes, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D011446:Prospective Studies; D019736:Prostheses and Implants / Q000382:microbiology*; D011474:Prosthesis Design; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D014640:Vancomycin