Lack of effect of prophylactic gentamicin treatment on intraocular and extraocular fluid cultures after pars plana vitrectomy.

摘要

BACKGROUND AND OBJECTIVE: To analyze the effect of preoperative prophylatic 0.3% gentamicin sulfate eyedrops on intraocular and extraocular fluid cultures after pars plana vitrectomy. PATIENTS AND METHODS: Forty consecutive patients undergoing pars plana vitrectomy were randomly assigned to receive either 0.3% gentamicin eyedrops or placebo preoperatively. Fluids from the vitreous cavity and from the conjunctival sac were collected for bacteriologic studies. RESULTS: Positive cultures from extraocular fluids were obtained in 30.4% of the gentamicin group and 35.3% of the placebo group (P = .75). Furthermore, 1 (3%) of 40 cultures of intraocular fluid and 13 (33%) of 40 cultures of extraocular fluid were positive. Culture growth positivity was not influenced by the patients' age, by diabetes, or by the duration of the operation. CONCLUSIONS: Prophylactic gentamicin treatment by the method applied in this study is not effective on reducing growth positivity. Contaminated extraocular fluid may play an important role in the pathogenesis of bacterial endophthalmitis following pars plana vitrectomy.