Use of routine antibiotic sensitivity testing for the management of corneal ulcers

To prospectively evaluate the clinical importance of antibiotic sensitivities for the management of corneal ulcers.

Thirty-two consecutive patients referred to the Cornea Service at Wills Eye Hospital, Philadelphia, Pa. between October 1, 1993, and May 31, 1994, with a culture-positive corneal ulcer were studied prospectively. Broad-spectrum empirical antibiotic therapy with intensive topical fortified antibiotics was initiated after smear and culture results were obtained. The therapy was modified based on clinical appearance, stain results, or organism identification. Clinicians were masked to the sensitivity results.

Fifteen patients healed after receiving the initial empirical antibiotic therapy (group 1). The antibiotic regimens of 6 patients were modified after the stain and/or culture results were available, although the clinical appearance suggested continued improvement while taking the initial regimen (group 2). Eleven patients had ulcers that either failed to improve or worsened after receiving the initial empirical therapy (group 3). Seven of these patients ultimately improved with a change in therapy; treatment failed in 4 patients. Nine patients (5 for whom antibiotic therapy succeeded and 4 for whom it failed) should have been adequately treated by the initial antibiotic therapy, according to sensitivity results. In the remaining 2 patients, in vitro sensitivity testing did not include the antibiotics used for the initial treatment. In all cases, the organisms were sensitive to the empirically altered regimen of antibiotics.

These preliminary results suggest that routine antibiotic susceptibility tests do not provide clinically useful information for the management of corneal ulcers. The identification of the organisms based on the results of smears and cultures was sufficient for the selection and modification of topical antibiotic therapy.