title: Capnocytophaga keratitis. A clinicopathologic study of three patients, including electron microscopic observations.
abstract: BACKGROUND
  Histopathologic studies of this unusual keratitis caused by Capnocytophaga species have not been reported previously.
  
  
  METHODS
  The authors report the light microscopic and ultrastructural findings of three patients with a distinctive necrotizing keratitis caused by an anaerobic gram-negative bacillus. In three patients, ages 19, 81, and 91 years, a necrotizing stromal keratitis developed; two of these patients had a previous penetrating keratoplasty for pseudophakic bullous keratopathy. The first patient did not have ocular surgery previously and was treated initially for presumed Acanthamoeba keratitis.
  
  
  RESULTS
  By light microscopy, all three keratectomy specimens were strikingly similar and showed a necrotizing and/or suppurative stromal keratitis displaying myriad slender, fusiform, gram-negative bacilli located anterior to Descemet's membrane and extending into the deep corneal stroma, assuming a "picket fence" appearance. Cultures of the cornea in case 1 grew Capnocytophaga ochracea. For the remaining two patients, a diagnosis presumptively was made based on characteristic histopathologic features. Results of electron microscopic examination showed numerous bacilli that were mostly extracellular; occasional organisms were phagocytosed by macrophages.
  
  
  CONCLUSIONS
  The histopathologic features of Capnocytophaga keratitis are unique; therefore, a presumptive diagnosis can be made based on the morphology and location of the bacilli in the keratectomy specimens. To the authors' knowledge, this is the first study describing the typical histopathologic and electron microscopic findings of Capnocytophaga keratitis.
authors.affiliation: Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030.
authors.forename: R L
authors.initials: RL
authors.lastname: Font
authors.forename: V
authors.initials: V
authors.lastname: Jay
authors.forename: R P
authors.initials: RP
authors.lastname: Misra
authors.forename: D B
authors.initials: DB
authors.lastname: Jones
authors.forename: K R
authors.initials: KR
authors.lastname: Wilhelmus
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002206:Capnocytophaga; D003319:Corneal Stroma / Q000382:microbiology / Q000473:pathology / Q000648:ultrastructure; D015818:Eye Infections, Bacterial / Q000382:microbiology / Q000473:pathology*; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000473:pathology*; D006801:Humans; D007634:Keratitis / Q000382:microbiology / Q000473:pathology*; D008297:Male; D008854:Microscopy, Electron