Treatment and Outcome of Nocardia Keratitis

Objective. To report our experience in treatment and outcome of Nocardia keratitis. Methods. Medical and microbiology records of seven cases of culture-proven Nocardia keratitis seen between January 1997 and March 1999 were reviewed retrospectively. In all patients, corneal scrapings were obtained for direct microscopic evaluation and culture. Drug sensitivity was determined by the Kirby–Bauer disk-diffusion method. The minimum inhibitory concentration of ciprofloxacin and amikacin for these isolates was determined by agar dilution method. Response to medical therapy and the end result were analyzed. Results. By the in vitro Kirby–Bauer disk-diffusion techniques, all isolates were sensitive to amikacin; six of these isolates were sensitive to gentamicin and four were sensitive to ciprofloxacin. The minimum inhibitory concentration (MIC) of amikacin for all isolates by the agar-dilution technique was well below the MIC breakpoint for Nocardia resistance, whereas the MIC of ciprofloxacin was above the MIC breakpoint for Nocardia resistance. All patients responded to medical therapy. The corneal infection resolved in three patients after treatment with ciprofloxacin, in one patient after fortified gentamicin, and in three patients after fortified amikacin. Outcome details were available for six patients. There was good visual recovery in four patients, with visual acuity of 20/25 or better in three. The cornea of two patients developed nonvascularized scars, and in four patients in whom the infiltrates were peripheral, vascularization was seen. Conclusions. Although patients of Nocardia keratitis may respond to other antibiotics, amikacin appears to be a drug of choice. In this small series, when appropriate therapy was initiated, Nocardia keratitis resolved promptly with good visual recovery.