Abstract
Abstract: :
Purpose: A 73 year old man with a history of diabetes mellitus and a failed corneal transplant presented with a Group B streptococcus (GBS) corneal ulcer. Despite treatment with topical fluoroquinolones the ulcer perforated and a panophthalmitis developed requiring enucleation. We therefore investigated in–vitro what might be the most effective topical ophthalmic antibiotic for the treatment for GBS keratitis. Methods: Isolated GBS was plated onto Mueller–Hinton agar with 5% sheep blood. 20 µl aliquots of the following topical ophthalmic preparations – gatifloxacin 0.3%, moxifloxacin 0.5%, ciprofloxacin 0.3%, sulfacetamide 10%, fortified vancomycin 50 mg/ml, fortified cephazolin 50 mg/ml, and balanced salt solution (BSS) – were added to sterile blank disks which were placed on the agar. The plate was incubated for twenty–four hours and the zones of inhibition were measured. Results: The topical ophthalmic preparations in–vitro produced inhibition zones of the following diameters: fortified cephazolin 50 mg/ml – 35 mm, moxifloxacin 0.5% – 30 mm, gatifloxacin 0.3% – 28 mm, ciprofloxacin 0.3% – 25 mm, fortified vancomycin 50 mg/ml – 22 mm, sulfacetamide 10% – 0 mm, and BSS – 0 mm. Conclusions: Group B streptococcus is a rare cause of ocular disease, poorly responds to antibiotic treatment and frequently leads to poor outcomes and severe visual loss. Of the topical ophthalmic antibiotic preparations tested in–vitro, GBS appears to be most sensitive to fortified cephazolin, least sensitive to fortified vancomycin, and resistant to sulfacetamide.
Keywords: antibiotics/antifungals/antiparasitics • bacterial disease