title: Failure of intravitreal dexamethasone to diminish inflammation or retinal toxicity in an experimental model of Bacillus cereus endophthalmitis.
abstract: OBJECTIVE
  To determine whether the usual clinical dose of intravitreal dexamethasone can attenuate intraocular inflammation and retinal necrosis in a rabbit model of fulminant Bacillus cereus endophthalmitis induced by crude exotoxins.
  
  
  METHODS
  Thirty-six eyes from pigmented mongrel rabbits received intravitreal injections of varying concentrations of crude B. cereus exotoxins with or without concomitant injections of 400 microg of dexamethasone sodium phosphate (0.1% solution). After ophthalmoscopic examination at 4 or 18 hr postinjection, the animals were killed and histopathologic findings graded.
  
  
  RESULTS
  Intraocular inflammation and retinal necrosis scores in eyes receiving both exotoxins and dexamethasone did not differ significantly from eyes receiving exotoxins alone for any exotoxin dose at 4 or 18 hr. The severity of retinal necrosis increased with toxin dose and was nearly maximal after 4 hr. Intraocular inflammation also generally increased with dose, but continued to increase until 18 hr.
  
  
  CONCLUSIONS
  Standard clinical doses of intravitreal dexamethasone do not appear to attenuate the intraocular inflammatory or tissue response to secreted B. cereus exotoxins. Other treatment modalities including vitrectomy, to decrease exotoxin load, and exotoxin inhibitors may be necessary for the effective treatment of B. cereus endophthalmitis.
authors.affiliation: Illinois Retina Associates S.C., Chicago, Illinois, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Pollack
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Beecher
authors.forename: Jose S
authors.initials: JS
authors.lastname: Pulido
authors.forename: Amy C
authors.initials: AC
authors.lastname: Lee Wong
mesh_terms: D000818:Animals; D001409:Bacillus cereus / Q000502:physiology*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000031:analogs & derivatives*; D004195:Disease Models, Animal; D009877:Endophthalmitis / Q000382:microbiology / Q000517:prevention & control*; D015818:Eye Infections, Bacterial / Q000382:microbiology / Q000517:prevention & control*; D005938:Glucocorticoids / Q000008:administration & dosage*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology / Q000517:prevention & control*; D007249:Inflammation / Q000517:prevention & control; D007267:Injections; D009336:Necrosis; D011817:Rabbits; D012160:Retina / Q000187:drug effects* / Q000473:pathology; D014822:Vitreous Body
chemical_list: D005938:Glucocorticoids; C004180:dexamethasone 21-phosphate; D003907:Dexamethasone