Prophylactic Antibiotics In Corneal Abrasion- Culture Results

Abstract

Objective: This is a prospective study to evaluate the effect of prophylactic antibiotic use in corneal abrasion on adnexial culture results. Also to study the effect of positive culture on healing of the abrasion. Methods: Conjunctival and lid margin cultures of 38 eyes with traumatic corneal abrasion were taken, all of them were then treated with topical chloramphincol 1.0 % ointment and patching. The variables considered were age group, gender, type of the abrasion, time before prophylactic antibiotic started, previous treatment by antibiotics and the initial abrasion size by slit-lamp examination and photographs of the fluoresceinstained cornea, which were performed on a daily basis until healing was complete. Photographs were analyzed for the healing process calculation using AutoCAD software. Results: A total of 38 patients, their mean ± S.D. age were 22.6 ± 15.1 years. Males were 27 and females were 11. Trauma was the cause of the corneal abrasion in 25 and the rest 13 were secondary to corneal foreign body removal. Twenty patients presented to us without previous intervention, and 18 patients received prophylactic antibiotic treatment and patched for 24 h before presentation. The rate of healing was calculated for 19 patients, who needed more than one visit for their defect to close; their mean ± S.D of linear speed of healing was 0.076 ± 0.053 mm / h and the mean ± S.D of surface speed of healing was 0.084 ± 0.107 mm² / h. Patients with defects closed by the first follow-up visit were 18, eight had positive cultures and 10 had negative cultures. Out of 37 cultures, 20 were negative and 17 were positive. The organisms identified were 13 staphylococcus epidermidis, 2 were streptococcus viridian, one culture grow Enterobacter cloacae and 1 culture grow staphylococcus aureus. Linear regression of the factors affecting the culture results was R² = 0.281 with P value = 0.838. Linear regression of the factors affecting the growth of different species was R² = 0.78 with P value = 0.007 for the age group only. Linear regression of the factors affecting the surface speed of healing was R² = 0.96 with P value approaching 0 for the surface area of the abrasion only. But the mean linear healing rate was 0.1 mm / h regardless of the initial abrasion diameter in abrasions ≥ 4 mm.