COMPARATIVE TREATMENT OF EXPERIMENTAL STAPHYLOCOCCUS-AUREUS ENDOPHTHALMITIS

PURPOSE: To compare treatment strategies for Staphylococcus aureus end ophthalmitis, we created an animal model in an aphakic rabbit eye and tested six different approaches to treatment. METHODS: Rabbit eyes wer e rendered aphakic, and three weeks postoperatively, S. aureus organis ms were injected into the vitreous cavity. One group was maintained as a control, Twenty four hours after bacterial injection, six different treatment groups were created for comparison. Clinical inflammation s cores, culture results 48 hours after treatment, histopathologic gradi ngs, and development of total corneal opacity three weeks after treatm ent were assessed. RESULTS: Injection of vancomycin hydrochloride into the vitreous cavity was more effective than injection of cefazolin so dium (P = .01) in reducing the percentage of eyes that had positive cu lture results and also resulted in lower inflammation scores. Vitrecto my plus injection of either antibiotic was more effective than injecti on of the same antibiotic alone in reducing culture-positive results a nd reducing clinical inflammation scores. Addition of systemic cortico steroids to intravitreal antibiotic injection did not improve any meas ure of outcome. Vitrectomy and injection of intravitreal vancomycin wa s the most effective strategy to sterilize the vitreous cavity, result ing in the lowest inflammation scores and the smallest percentage of e yes with opaque corneas. CONCLUSION: In an animal model of S. aureus e ndophthalmitis, the combination of vitrectomy and injection of intraoc ular vancomycin was the most effective strategy for rapidly controllin g the infective process and improving the outcomes measured three week s after treatment.