Rapid diagnosis of fungal keratitis in patients with corneal ulcer using Calcofluor White stain

Abstract

Background: The prevalence of fungal keratitis has risen in recent years significantly. To avoid additional complications, diagnosing and treating fungal keratitis is crucial. This study aims to measure the efficacy of a calcofluor white (CFW) stain for the quick diagnosis of fungal keratitis and to contrast the positive rates, sensitivity, and specificity with a 10% potassium hydroxide (KOH)-based smear and culture technique. Methods:From individuals with clinically suspected corneal ulcers, 30 corneal scrapings had been collected. Data on demographics had been analyzed. Results: Of the 30 patients, 40% were women and 60% were men. There was a 1.5:1 man-to-woman ratio. The age of patients ranged from 29 to 71 years (mean 46.67 ± 10.90). The age presentation of those between the ages of 41 and 50 years was the most frequent (36.7%). The majority of cases were farmers (43.3%). Trauma was the most common predisposing factor (46.6%). Twenty-four (80%) cases were culture positive. Eleven (36.7%) were fungal, 13 (43.3%) were bacterial and 6 (20%) showed no growth. Fusarium was the most common fungal isolate (36.4%), followed by Aspergillus (27.3%). While Staphylococcus aureus was the most common bacterial isolate (46.2%), followed by Pseudomonas (38.4%). The sensitivity of KOH wet mount and CFW stain was 72.7% and 90.9%, respectively. The specificity of both KOH wet mount and CFW stain was 100%. Conclusion:The early diagnosis of fungal keratitis can be made rapidly by direct microscopic examination of fungal elements using CFW stain. When diagnosing fungal keratitis, CFW has higher sensitivity to KOH.

Keywords

• keywords: fungal keratitis
• corneal ulcer
• potassium hydroxide wet mount
• calcofluor white stain