Experimental pseudomonal posttraumatic endophthalmitis in a swine model. Treatment with ceftazidime, amikacin, and imipenem

Abstract

Purpose: To compare the intravitreal efficacy of three separately administered antibiotics (imipenem, ceftazidime, and amikacin) in limiting the intraocular inflammation and tissue destruction caused by posttraumatic pseudomonal endophthalmitis.

Methods: Thirty-three Yorkshire pigs each received a surgically induced scleral injury to the right eye. After repair, each eye was injected with 22,000 colony-forming units of live Pseudomonas aeruginosa. Pigs then were randomly grouped into a natural-history-of-infection group in which no treatment was given (n = 9) or into groups treated with the following: intravitreal imipenem (n = 6), ceftazidime (n = 6), amikacin (n = 6), or normal saline (n = 6). Pigs then were observed clinically for 18-24 hours after surgery and enucleated for histopathologic examination.

Results: Clinical examinations revealed significantly less posterior segment inflammation in pigs treated with amikacin and imipenem than in pigs in the natural history or saline control groups, based on the Wilcoxon rank sum test (P < .05). Histopathologic examinations showed similar results, with less intraocular inflammation and retinal destruction in pigs treated with amikacin and imipenem, whereas the inflammation in pigs treated with ceftazidime did not differ significantly from that in control pigs.

Conclusion: Intravitreal antibiotic treatment with imipenem or amikacin appears to limit intraocular inflammation and retinal tissue damage when given early in the course of posttraumatic pseudomonal endopthalmitis. Results with ceftazidime are less conclusive.