Aqueous humor antimicrobial activity: in vitro analysis after topical 0.5% chloramphenicol application

Purpose: To assess aqueous humor antimicrobial activity in vitro after topical 0.5% chloramphenicol application. Materials and methods: This investigation included 63 eyes from 65 cataract surgery patients. The study group of 48 eyes received preoperatively four topical applications of 0.5% chloramphenicol. The control group of 15 eyes was given no topical applications. Aqueous humor samples were collected for in vitro antimicrobial analysis using Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Pasteurella multocida organisms by means of disk diffusion test. Results: No inhibition halo was observed around all aqueous humor samples from all chloramphenicoltreated patients, irrespective of the sample quantity added to the paper disks, with no significant difference from aqueous humor from untreated control patients. Conclusions: Aqueous humor displayed no bactericidal effect against any of the microorganisms evaluated after topical 0.5% chloramphenicol application.