A case report of corneal abscess caused by Nocardia farcinica

Abstract

Background: Keratitis caused by Nocardia, a Gram-positive bacterium prevalent in soil, is an infrequent ocular infection typically following corneal trauma or exposure to soil or vegetation. Nocardia farcinica, in particular, is an exceedingly rare causative agent of keratitis, with few documented cases worldwide and none previously reported in Vietnam.

Case Presentation: We report the first documented case of N. farcinica keratitis in Viet Nam, presenting as a corneal abscess in a 70- year-old male farmer following phacoemulsification surgery. Despite prolonged treatment with corticosteroids and atropine eye drops, the patient experienced persistent pain, tearing, and poor vision improvement. A definitive diagnosis was achieved through the culture of corneal swabs on blood agar medium, which yielded dry, wrinkled yellow colonies identified as Nocardia spp., with subsequent MALDI-TOF MS (VITEK-MS) confirmation of N. farcinica. The patient showed significant improvement following treatment with 0.3% tobramycin.

Conclusion: This case underscores the importance of considering N. farcinica in the differential diagnosis of post-surgical keratitis, particularly in patients unresponsive to standard treatments. It highlights the necessity of a thorough medical history, clinical examination, and the pivotal role of microbiological culture and molecular identification techniques in diagnosing rare infectious agents. This case adds to the global repository of Nocardia keratitis cases and suggests a need for awareness and diagnostic readiness for such infections, especially in rural farming communities.