title: Scanning Electron Microscopic Analysis of Biofilm Formation in Explanted Human Boston Type I Keratoprostheses.
abstract: OBJECTIVE
  To describe the morphological distribution of host tissue and microbial biofilms on the intraocular surfaces of Boston type I keratoprostheses (KPros) explanted because of corneal melt.
  
  
  METHODS
  Retrospective study of scanning electron microscopy (SEM) images from 4 explanted Boston type I KPros composed of polymethylmethacrylate and titanium. SEM images of KPro-associated ocular surfaces were reviewed for the presence of inflammatory cells, microbes, and/or biofilm formation. One sterile type I KPro was also imaged to serve as a (device only) control.
  
  
  RESULTS
  All 4 KPros were explanted because of culture-negative, clinically "sterile" donor corneal melt with impending KPro extrusion. In all cases, the rough, irregular surfaces of the device harbored more adherent corneal epithelium and stromacytes, inflammatory cells, and bacteria than the smooth, polished surface of the KPro optic. Two KPros showed not only evidence of prior bacterial colonization but marked biofilm formation.
  
  
  CONCLUSIONS
  SEM images of explanted KPros explanted for "sterile" corneal melt demonstrated evidence of biofilm formation despite negative donor corneal cultures and the absence of clinical suspicion for infection. These results suggest that "sterile" corneal melt may be due to inflammatory host responses to low microbial burdens as seen in biofilms and/or released antigens after antibiotic-induced lysis. There was increased adherence of host tissue cells and microbial biofilms on the nonpolished surfaces of the KPro. Polishing the intraocular polymethylmethacrylate and titanium KPro surfaces may decrease microbial adhesion and biofilm formation in human subjects with KPros, but what impact this will have on rates of postoperative endophthalmitis is unknown.
authors.affiliation: *Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL; †Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL; ‡Department of Ophthalmology, University of Minnesota, Minneapolis, MN; §Microbiology and Molecular Biology and Ophthalmology, Tufts University School of Medicine, Boston, MA; ¶Infectious Diseases, Mount Auburn Hospital, Cambridge, MA.
authors.forename: Kavitha R
authors.initials: KR
authors.lastname: Sivaraman
authors.forename: Joshua H
authors.initials: JH
authors.lastname: Hou
authors.forename: Jin Hong
authors.initials: JH
authors.lastname: Chang
authors.forename: Irmgard
authors.initials: I
authors.lastname: Behlau
authors.forename: M Soledad
authors.initials: MS
authors.lastname: Cortina
authors.forename: Jose de la
authors.initials: Jde L
authors.lastname: Cruz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001187:Artificial Organs; D018441:Biofilms; D002648:Child; D003315:Cornea / Q000601:surgery*; D003316:Corneal Diseases / Q000601:surgery*; D019573:Epithelium, Corneal / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D019736:Prostheses and Implants; D012189:Retrospective Studies