Isolation of Nocardia Otitidiscaviarum from a Case of Cutaneous Nocardiosis: A Rare Case Report

Abstract Nocardia species are Gram-positive, partially acid-fast, filamentous bacilli commonly found in soil, water, and air. In humans, Nocardia typically causes respiratory, neurological infections and, less frequently, cutaneous infections. While Nocardia brasiliensis is the predominant species implicated in cutaneous nocardiosis, Nocardia otitidiscaviarum —a less commonly isolated species—can cause localized or disseminated infections, even in immunocompetent individuals. Mycetoma is a chronic, disfiguring granulomatous disease caused by various pathogens. Accurate identification of the causative agent is essential for determining the appropriate treatment and prognosis. Culture remains the gold standard for definitive diagnosis. Here, we report a rare case of actinomycetoma caused by Nocardia otitidiscaviarum in a 41-year-old immunocompetent female. The organism was isolated from purulent discharge collected from draining sinuses on her foot. Identification was achieved through microscopic examination and culture, with species confirmation performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).