Abstract
Abstract: :
Purpose:Linezolid (LN) is a synthetic antibiotic of the oxazolidinone class with inhibitory activity against gram–positive bacteria including methicillin–resistant Staphylococcus aureus (MRSA), vancomycin–resistant enterococci (VRE), and penicillin–resistant Streptococcus pneumoniae. Linezolid also exhibits activity against some anaerobes including Propionbacterium acnes, Peptostreptococcus spp. Bacteroides fragilis, C. difficile, and C. perfringens. We evaluated the intravitreal toxicity of 400 mcg/0.2 ml concentration of linezolid in albino rabbits Methods: One eye of 17 New Zealand white rabbits was injected with either 400 mcg of LN (13 eyes) or balanced salt solution (4 eyes). An anterior paracentesis was performed prior to the injection to prevent an intraocular pressure (IOP) rise. Post–injection, fundus exams were performed and intraocular pressures taken on days 3, 14, and 56. The rabbits were sacrificed and the globes enucleated after 3 days (4 eyes), 14 days (3 LN; 1control), and 56 days (6 LN; 3 control). Histopathologic examination of the eyes was performed and the retinal and ocular changes evaluated using a semiquantitative score in a masked fashion. Results: On fundus exam, no eye exhibited signs of intraocular inflammation or precipitation. The IOP’s were all within the normal range (15–22 mmHg). Histopathologic examination showed trace to 1+ vacuolization in the nerve fiber layer (6 LN eyes; 3 control eyes) or trace to 1+ (1 eye 2+) ganglion cell loss. (3 LN eyes, 0 control eyes). The remaining retinal layers and ocular structures were unremarkable. Conclusions: 400 mcg per 0.2ml intravitreal linezolid appears to be safe and well tolerated in rabbit eyes. Further studies should be performed to investigate whether intravitreal linezolid may be a viable alternative to intravitreal vancomycin in the prevention and treatment of endophthalmitis
Keywords: drug toxicity/drug effects • antibiotics/antifungals/antiparasitics • endophthalmitis