Lab Diagnosis and Evaluation of Fungal Keratitis

Abstract

Objective: This study is aimed to evaluate the usefulness of   Sabouraud dextrose agar in the confirmatory diagnosis of suspected cases of fungal keratitis.

Study Design: Pre-designed prospective study of corneal scrapings obtained after detailed slit-lamp examination and documentation from all patients seen for non-viral microbial infective keratitis.

Place and Duration of Study: This study was conducted in the Department of Ophthalmology, JPMC, Karachi from July 2008 to June 2011.

Materials and Methods: 128 cases of non-viral microbial infective keratitis. Corneal scrapings of 128 patients with microbial keratitis Smears of corneal scrapings were stained with Gram’s Method and inoculated specimens on Sabouraud dextrose agar (SDA) and incubated for 3-4 days.

Results: 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 positve cocci on smears and were negative for SDA.

Conclusion: 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.