Pattern of Fungal Corneal Ulceration at Tilganga Institute of Ophthalmology

Abstract

Corneal ulcer is a leading cause of ocular morbidity and blindness worldwide. Among the corneal diseases, fungus keratitis or fungal corneal ulcers form major blinding eye disease. This study was conducted to isolate and identify fungal pathogens involved in corneal ulcers. A total of three hundred corneal scrapings were collected from the suspected patients visiting Out Patients Department ward of Tilganga Institute of Ophthalmology from July 2010 to February 2011 and subjected to microscopic observation and culture. Corneal scrapings were smeared onto three slides to prepare 10% KOH wet mount or Lactophenol Cotton Blue stain, Gram’s stain and Giemsa stain. Also, samples were streaked directly onto the surface of Sabouraud’s Dextrose Agar, Blood Agar, Chocolate Agar and in Thioglycolate Broth which were incubated at 27ºC in aerobic condition for 7 days to 28 days and these plates were observed for fungal growth. Out of 300 samples collected, 21% (n=63) samples had shown growth of fungal pathogens. Out of 63 fungal isolates, majority of the isolates i.e. 38.1% (n=24) were identified as Aspergillus spp followed by Fusarium spp 19% (n=12) and Curvularia 14.3% (n=9) respectively. Other fungal isolates included Cladosporium (7.9%), Penicillium (7.9%), Acremonium (4.8%), Bipolaris (3.2%) Candida albicans (3.2%) and Rhizopus (1.6%). Altogether, 52.7% (n=158) samples were collected from male patients and 47.3% (n=142) samples were collected from female patients. Rate of infection was found to be higher in males (27.2%) than females (14.1%) but there was no significant difference between the males and females (p=0.157). The mean age calculated was 44.8 years in male and 41.7 years in female. The highest number of fungi was isolated from 31-40 (23.8%) age group followed by 51-60 (22.2%) age groups. Agricultural worker group were mostly infected. The rate of infection was higher in the months of November and December. Filamentous forms of fungi were found in higher number than non- filamentous forms. Among the filamentous fungi, Aspergillus was the most frequently isolated followed by Fusarium and Curvularia respectively. Aspergillus fumigatus (62.5%) was the most frequently isolated Aspergillus species.