|Description:||This hematoxylin-eosin (H&E) stained photomicrograph of a tissue sample of a mycetoma excised from a patient’s thorax ill with nocardiosis, revealed the presence of a tissue granule due to the bacterium, Nocardia brasiliensis.|
Overall, 80% of nocardiosis cases present as invasive pulmonary infection, disseminated infection, or brain abscess; 20% present as cellulitis. Pulmonary infection commonly presents with fever, cough, or chest pain. Central nervous system (CNS) symptoms include headache, lethargy, confusion, seizures, or sudden onset of neurologic deficit.
The majority of cases are caused by the Nocardia asteroides complex (at least 50% of invasive infections). The N. asteroides complex is comprised of N. abscessus, N. cyriacigeorgica, N. farcinica, and N. nova. Other known pathogenic species of Nocardia include N. transvalensis complex, N. brasiliensis, and N. pseudobrasiliensis.