Lab diagnosis and evaluation of fungal keratitis

ABSTRACT

This study is aimed to evaluate the usefulness of Sabouraud dextrose agar in the confirmatory diagnosis of suspected cases of fungal keratitis. Pre-designed prospective study of corneal scraping obtained after detailed slit-lamp examination and documentation from all patients seen for non-viral microbial infective keratitis. This study was conducted in the Department of Ophthalmology, JPMC, Karachi from July 2008 to June 2011. 128 cases of non-viral microbial infective keratitis. Corneal scraping of 128 patients with microbial keratitis Smears of corneal scraping were stained with Gram's Method and inoculated specimens on Sabouraud dextrose agar [SDA] and incubated for 3-4 days. In a series of suspected cases of fungal keratitis, 119/128 [75% patients] had positive results for fungus in corneal scrapings by direct microscopy using Grams staining method and culture on Sabouraud dextrose agar [SDA]. 43% males and 32% females had Candidial keratitis and 11% males and 7% females had Fusarium infection. Other samples showed presence of Gram positive cocci on smears and were negative for SDA. Fungal keratitis continue to be an important cause of ocular morbidity, since it becomes difficult to clinically diagnose and differentiate between bacterial and mycotic keratitis in complicated cases. It is better to use a standard culture medium like Sabouraud agar [SDA] when confirming ocular mycosis