Nocardia keratitis: Microbiological characteristics, antibiotic sensitivity, and clinical profile in a tertiary care setting

Abstract: PURPOSE: This study evaluates the clinical characteristics, microbiological profile, and management strategies of Nocardia keratitis in patients referred to Farabi Eye Hospital, a tertiary care center. METHODS: This retrospective study on culture-proven Nocardia keratitis (2014–2024) included biomicroscopic examinations, visual acuity assessments, and culture-based diagnoses. It analyzed risk factors, clinical features, and antibiograms, with treatments consisting of fortified antibiotics and surgical interventions. RESULTS: A total of 38 patients were included in the study, with 16 requiring inpatient management and 22 managed as outpatients. The mean duration from symptom onset to presentation was 28.62 (median = 4.0) days, and the mean infiltration size was 2.7 ± 1.0 mm. Contact lens (CL) use was the most common risk factor, identified in eight patients (21.1%). There were no significant differences in age, infiltration size, presenting visual acuity (logMAR), or admission duration between CL users and nonusers ( P > 0.05). The mean visual acuity was 1.56 logMAR at presentation and showed a slight, nonsignificant improvement to 1.49 logMAR at discharge ( P = 0.3). Surgical intervention was required in eight patients (50% of admitted cases), with penetrating keratoplasty performed in five patients (31.3%). Three cases developed endophthalmitis. All isolates (100%) were susceptible to amikacin, while 91.7% were susceptible to imipenem. CONCLUSION: Nocardia keratitis, though rare, can lead to vision-threatening complications with a prolonged course. Recognizing risk factors like CL use and ocular trauma is crucial, and while amikacin is the primary treatment, alternatives like imipenem may be effective in certain cases.