Nocardia keratitis

Purpose of review: Nocardia keratitis is a rarity in most parts of the world. If the diagnosis is timely, and appropriate treatment started, then the visual outcome is good. The purpose of this review is to discuss the recently published literature in relation to the epidemiology, cause, diagnosis, and therapy of Nocardia keratitis.

Recent findings: The incidence of Nocardia keratitis, although not well established, appears to be increasing with new species identified with newer molecular methods. The different species causing keratitis are Nocardia. arthritidis, N. neocaledoniensis, N. asiatica, N. asteroids type IV, N. brasiliensis, N. pseudobrasiliensis, N. cyriacigeorgica, N. farcinica, N. otitidiscaviarum, and N. transvalensis. Current therapies with fortified amikacin and newer fluoroquinolones are effective, provided the diagnosis has been made in good time. Ongoing research toward rapid diagnosis using various molecular techniques seems to be promising. Diagnostic microbiology laboratories need to be familiar with these organisms especially in endemic areas, and it is important for the clinician to notify the suspicion of such cases.

Summary: The current recommended treatment is amikacin, and with appropriate therapy, Nocardia keratitis resolves with scarring, with or without vascularization, resulting in good visual outcome.