Fungal corneal ulcer: A prospective study on the causative fungus and the response to the present treatment protocol at ANIIMS, Andaman and Nicobar Islands-first time present

Abstract

Background: Fungal keratitis accounts for 50% of all microbial keratitis, depending upon the geographic location. Filamentary fungi are predominant in tropical and subtropical climates. Treatment is given based on clinical diagnosis supported by the presence of fungus in potassium hydroxide (KOH) mounting, rather than on culture report because culture takes time. Reported studies from northern part of the country revealed Aspergillus as the most common fungus, whereas Fusarium was reported to be the most common fungus in southern part of the country. Aspergillus fumigatus is the most common fungus isolated in our study and the response to standard treatment is good. Aim of the Study: To identify spectrum of fungi, response to the standard treatment given, and sensitivity of KOH preparation in clinically diagnosed fungal corneal ulcers and to identify the predisposing factors and culture-positive cases (both Sabouraud's and blood culture). Methods: All patients who were clinically diagnosed to have fungal corneal ulcer, based on history, clinical features, and slit-lamp findings over a period of 1 year, were included in the study. All patients were subjected to corneal scraping and the material was examined by KOH mounting, Gram staining, and specific culture techniques. The ulcer was treated as per the standard treatment protocol followed in the institution, and the response to treatment was analyzed. Results: The study included 40 patients, with males being predominated (n = 36). KOH positivity was seen in 34 (85%) cases whereas KOH negativity was seen in 6 (15%) cases. Gram stain was positive in 6 (15%) cases. The culture was positive in all cases (100%). The most common fungus isolated was A. fumigatus – 24 (60%) cases. The response to the treatment after 8 weeks was found in 34 (85%) cases. Enucleation was done in 7 (17.5%) cases. Total therapeutic keratoplasty was done in 7 (17.5%) cases. Total penetrating keratoplasty was done in 4 (10%) cases. Conclusions: Rapid diagnosis and early institution of antifungal therapy are necessary to prevent ocular morbidity and blindness. Although culture helps in definite diagnosis and identification, direct microscopic detection of fungal structures in corneal scrapes permits a rapid presumptive diagnosis.

Keywords

• Corneal infections
• fungal keratitis
• mycotic keratitis