Clinical Analytical Study of Microbial Keratitis in a Tertiary Care Institution

Aim: To study the epidemiologic characteristics, risk factors, etiology, relevance of gram stain and culture, response to treatment and outcome of microbial keratitis in the general adult population. Material and Methods: Study Design: A prospective, nonrandomized, analytical clinical Study of 100 cases presenting with suspected microbial keratitis presenting to the Cornea clinic, Department of Ophthalmology, Tirunelveli Medical College Hospital were examined according to a dedicated corneal ulcer protocol. Study period: August 1, 2011 and July 31, 2016. Inclusion criteria: greater than16 years of age, corneal infiltration, microbiological tests of scrapings Exclusion criteria: viral keratitis, keratitis of noninfective etiology and children below 16 years of age. Corneal ulcer scrapings were subjected to gram stain and culture and sensitivity. The clinical outcomes were tabulated. Results and Discussion: The 40-50 years group was the most affected. There was no sex preponderance. Staphylococcus spp were the most common organism isolated. Pseudomonas was the most common gram negative bacterium isolated. Gatifloxacin (0.3 %) was the most effective antibiotic according to sensitivity reports. Fortified cefazidime (50 mg/ml) and amikacin (20mg/ml) were effective on gram negative bacteria when added to topical gatifloxacin. Poor outcomes were significantly associated with older age ( p=0.021708), large ulcers (p=0.000032), central ulcers (p=0.00001) and presence of hypopyon (p=0.000012). Conclusion: Topical gatifloxacin (0.3 %) is the antibiotic of choice for initial monotherapy of bacterial keratitis. Fortified amikacin (20mg/ml) or fortified ceftazidime (50mg/ml) must be added to gatifloxacin 0.3 % if gram negative bacilli are identified. Modification of initial antibiotic based on antimicrobial sensitivity is needed only when worsening of the ulcer occurs clinically.