Microbial Inhibitional in Non-inflamed Human Aqueous after Oral Antibiotic Intake

To investigate the penetration of cefixime, cephalexin and ciprofloxacin into the human eye based on microbial inhibition by human aqueous samples after oral administration. Sixty patients aged 40 to 75 years who were scheduled for cataract surgery were divided into three equal groups. One group received 500 mg oral ciprofloxacin 24, 12 and 2 hours preoperatively; another group received 500 mg oral cephalexin 24, 18, 12, 6 and 2 hours before the operation and the third group received 400 mg oral cefixime 24, 12 and 2 hours prior to surgery. Immediately before opening the anterior chamber, 0.1 ml of aqueous was taped with an insulin syringe. A 4 ml sample of the patient’s blood was obtained simultaneously. Aqueous and serum specimens as well as a standard antibiotic disc were placed on the culture media of a known bacterium which was completely sensitive to the respective antibiotic. After 48 hours microbial inhibition zone of each sample was compared to the standard antibiotic disc. No microbial inhibition zone was seen by aqueous samples, however very large zones of inhibition were seen by discs of serum samples and antibiotics. It seems that oral cefixime, cephalexin and ciprofloxacin do not achieve effective concentrations in human aqueous for microbial inhibition.