Failure of intravitreal dexamethasone to diminish inflammation or retinal toxicity in an experimental model of Bacillus cereus endophthalmitis

John S. Pollack, Douglas J. Beecher, Jose S. Pulido, Amy C.Lee Wong

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Purpose. 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 μg 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.

Original languageEnglish (US)
Pages (from-to)253-259
Number of pages7
JournalCurrent Eye Research
Volume29
Issue number4-5
DOIs
StatePublished - Oct 1 2004

Keywords

  • Bacillus cereus
  • Dexamethasone
  • Endophthalmitis
  • Exotoxins
  • Intraocular inflammation

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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