Purpose
Previous studies have pointed out the need for broad antibiotic coverage in infectious keratitis. With increasing rates of antibiotic resistance, the method of empiric treatment of infectious keratitis should be revisited frequently through retrospective analysis of organisms isolated from these infections.
Methods
A retrospective chart review of all cases of infectious keratitis was performed for all patients presenting to a Level 1 Eye Trauma hospital between 2010 and 2012. Data included patient demographics, source of culture, bacterial or fungal organism cultured, and susceptibility profiles for positive bacterial cultures. An antibiogram was constructed from all positive cultures.
Results
A total of 289 culture positive cases of infectious keratitis occurred over the three year period observed. Of the positive cultures, 41 (14%) grew multiple microbes. Thirty-five (10.6%) of the cultures were fungal isolates. Two hundred nineteen (66%) of the cultures were gram-positive bacteria, and all Gram positive organisms were susceptible to vancomycin. The antibiotics with the highest sensitivities were vancomycin (100%), ceftriaxone or cefotaxime (100%), tobramycin (100%), linezolid (100%), cefepime (100%), rifampin (98.6%), meropenem (97.6%), gentamicin (96.0%), tetracycline (90.16%), and trimethoprim-sulfamethoxazole (87.80%). Rates of fluoroquinolone sensitivity ranged from 67.47% (ofloxacin) to 84.26% (levofloxacin).
Conclusions
Infectious keratitis is a serious cause of visual loss, and treatment is often initiated prior to culture and sensitivity results. Susceptibility testing reveals that most organisms are susceptible to vancomycin, tobramycin, and third-generation cephalosporins with no resistant strains found. Growing rates of resistance to commercially available antibiotics should drive the development of better empiric treatments for bacterial keratitis.
Keywords: 573 keratitis •
479 cornea: clinical science •
422 antibiotics/antifungals/antiparasitics