A Study on Microbial Profile of Corneal Ulcer Cases in a Tertiary Health Care Centre of Southern Assam

Abstract

Background-Visual impairment due to corneal ulceration has for long been acknowledged as leading cause of blindness both worldwide and in India only next to Cataract. The aetiology for infective corneal ulcer varies considerably with occupation of patients in different regions of India. Thus, continuing with empirical management without lab diagnosis leads to protracted clinical course. So, understanding the microbial profile of corneal ulcers in agriculture dependent population of Southern Assam helps in improved management of this morbidity. Aims- To 1) Find the prevalence of infected corneal ulcers in untreated patients attending Ophthalmology department of a tertiary care hospital of Southern Assam. 2) Study the pattern of microbial aetiology in the infected corneal ulcer cases. 3) Find the association of infected corneal ulcers with various attributing factors. Method-Corneal scrapings from 86 routine untreated cases of corneal ulceration from Ophthalmology Department were studied prospectively from Dec2017 to Jan2019 and subjected to Gram staining and direct examination with 10%KOH. Culture on SDA and Blood Agar were incubated at 25°C and 37°C respectively and followed up for 3 weeks before declaring sterile. Antimicrobial sensitivity was performed for bacterial isolate and yeast-like species. Slide culture and LPCB tease mount were done for identification of moulds. Result- Out of the 86 cases, 58 were positive in direct microscopy, of which 44 were culture positive. Of the 28 samples negative in direct microscopy, 2 were positive by Culture. Bacterial isolates were found in 5 cases and fungal aetiology in 41 cases. Conclusion- The prevalence of infected corneal ulcer as per standard of Culture positivity is 53.5% (46/86). Mycotic involvement was found in 90% cases. Important fungal isolates identified were Aspergillus species, Penicillium species, Curvularia species, Fusarium species, Sarocladium species. Higher prevalence was significantly associated with harvesting season, agricultural practice and history of trauma while diabetes and steroid intake were not significantly associated with mycotic ulcers. Keywords: Corneal ulcer, Assam, Fungal, Fusarium, Sarocladium, Pseudomonas.