Effect of intracameral antibiotic supplementation at the end of cataract surgery - An experimental model

Purpose; To study the effect of intracameral injection of Polymyxin B and Bacitracin in reducing bacterial colonization in experimental cataract surgery in vitro and in vivo. Methods: I. In vitro model: sterilized artificial chambers were inoculated with 107 log phase organisms of Staphylococcus aureus or Pseudomonas aeruginosa prior to cataract surgery. Phacoemunification was simulated, then O.lml of Polymyxin B (10U) and O.lml of Bacitracin (1000U) were injected into the chamber. Fellow eyes served as controls. Anterior chamber samples were aspirated immediately and at 24 hours and inoculated for quantitative bacteriology. II. In vivo model: 107 log phase S. aureus was injected into the anterior chamber of 5 rabbits. Phacoemulsification was performed and O.lml of Polymyxin B (IOU) and O.lml of Bacitracin (1000U) were injected into the anterior chamber of 5 rabbits. 5 rabbits served as a control group and received BSS alone. Quantitative bacteriology was performed from aspirates taken at 24 hours. Results! Intracameral antibiotic injection resulted in a statistically significant (p < 0.05) reduction in bacterial colonization 24 hours after the surgery as compared to controls in both models. Conclusions: Controlled intraocular administration of Polymyxin B/Bacitracin has an appreciable effect in decreasing bacterial colonization. Further studies addressing toxicity are warranted.