Clinical manifestations of nocardiosis

Nocardiosis is caused by environmental Gram-positive Actinobacteria of the Nocardia genus. It is found throughout Australia but more commonly in tropical and subtropical regions.

Single or multiple skin lesions can occur in immunocompetent individuals. Disseminated disease usually occurs in immunocompromised patients, and is commonly associated with central nervous system infection with brain abscesses. Pulmonary Nocardia ranges from mild acute or mild chronic disease with minimal or no changes on chest X-ray, to severe multilobar disease with high mortality. Consider testing patients with severe or disseminated Nocardia for an immune system disorder (eg HIV).

Except in immunocompetent patients with localised cutaneous disease (in whom imaging should be considered on a case-by-case basis), chest X-ray and brain computed tomography (CT) or magnetic resonance imaging (MRI) (both with contrast) are recommended to assess for pulmonary and neurological disease.