Purpose: To report the clinical and microbiological characteristics and treatment outcome of bacterial keratitis at a tertiary eye care center in eastern India.
Design: Retrospective analysis of medical and microbiology records.
Methods: All patients had undergone complete clinical and microbiological evaluation for microbial keratitis. Patients with laboratory-proven bacterial keratitis were included in the study.
Results: Between July 2006 and December 2010, 1417 microbial keratitis was clinically diagnosed in the patients. Whereas no organisms were found in 27.8% (394/1417) of cases, 21.4% (303/1417) were bacterial. From 303 patients, 347 bacterial isolates were cultured, 260 (74.9%) of which were gram-positive, 67 were gram-negative, and 20 were acid-fast. Streptococcus pneumoniae was the predominant isolate (86/347 [24.7%]), followed by Staphylococcus species [64/347 (18.4%)]. Pseudomonas aeruginosa (29/347 [8.3%]) was the most common gram-negative bacterial isolate. High level of susceptibility to cefazolin (96.2%) and vancomycin (96.5%) was found in gram-positive cocci, whereas susceptibility of Pseudomonas species to gatifloxacin was 95.1%. Fifty-three patients (17.5%) required tissue adhesive, and 47 (15.5%) needed penetrating keratoplasty. Healed corneal scar was achieved in 188 patients (62%), whereas 34 (11.2%) were lost to follow-up. Large stromal infiltrate size, older age group, and poor presenting visual acuity were significant factors that adversely affected final outcome (P < 0.05).
Conclusions: Proportion of bacterial keratitis was low compared with other studies from India. Gram-positive bacteria were a common cause of bacterial keratitis with high susceptibility to cefazolin and vancomycin. Gram-negative bacteria were sensitive to gatifloxacin with overall good treatment outcome.