Epidemiological and Microbiological Profile of Infective Keratitis at a Tertiary Care Centre in Central Zone of Kerala, India

摘要

Introduction: Infective keratitis is a potentially vision threatening condition caused by various microbial etiology. Due to high virulence and rapid progression of many etiological agents, any corneal inflammation should be considered a potential threat to vision, requiring immediate evaluation and treatment. Evaluation of epidemiological and microbiological profile of infective keratitis of a region can significantly contribute towards appropriate management of this ophthalmic emergency.Aim: To study the bacterial and fungal etiological agents and the epidemiological factors associated with infective keratitis in patients attending the Ophthalmology Department of Government Medical College, Thrissur, Kerala, India.Settings and Study Design: In this cross-sectional study, a total of 135 corneal scrapings were evaluated from patients presenting with corneal ulcers from December 2012 to May 2014.Materials and Methods: Scrapings were subjected to Gram staining, KOH wet mount and culture for bacterial and fungal pathogens. Isolates were identified by conventional methods and their antibiotic susceptibility pattern was established.Statistical Analysis: The results were analysed by mean, Chi-square test and Fisher’s exact test.Results: Corneal trauma was the main risk factor associated with infective keratitis (59.3%) and vegetative matter was the most common trauma type observed (36.3%). Culture was positive in 35.56% of cases, of which 18.52% were bacterial and 17.04% were fungal. Gram positive cocci were the predominant isolates (64%). Staphylococcus epidermidis was the most common bacterial isolate (32%), followed by Streptococcus pneumoniae and Pseudomonas aeruginosa (16% each). Fusarium species was the most common fungal isolate (39.13%), followed by Curvularia species and Aspergillus species (13.04%). Unidentified dematiaceous fungi accounted for 17.39%. Sensitivity of Gram stain in bacterial and fungal detection was 56% and 39%, while specificity was 95% and 96% respectively. Sensitivity and specificity of KOH wet mount examination in the detection of fungal elements was observed as 82% and 91% respectively.Conclusion: Our study observed corneal injury as the main risk factor associated with infective keratitis. Males were more affected than females. Staphylococcus epidermidis and Fusarium species were the commonest bacterial and fungal isolates respectively. Geographical variation persists in microbial etiology of infective keratitis.