Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 33-34: Nocardiosis + Key Features Download Section PDF Listen +++ ++ Nocardia species are an aerobic filamentous soil bacterium that can cause pulmonary and systemic nocardiosis Commonly identified nocardia species include members of the Nocardia asteroides complex and Nocardia brasiliensis Bronchopulmonary abnormalities (eg, alveolar proteinosis) predispose to colonization, but infection is unusual unless the patient is also receiving systemic corticosteroids or is otherwise immunosuppressed Central nervous system (CNS) involvement commonly accompanies pulmonary infection + Clinical Findings Download Section PDF Listen +++ ++ Pulmonary involvement usually begins with malaise, loss of weight, fever, and night sweats Cough and production of purulent sputum are the chief complaints Pulmonary infiltrates may penetrate to the exterior through the chest wall, invading the ribs Dissemination from pneumonia may involve any organ, especially CNS, skin, and bone, or there may be primary cutaneous disease Brain abscesses and subcutaneous nodules are most frequent Cutaneous lesions may mimic actinomycosis Dissemination is seen exclusively in immunocompromised patients + Diagnosis Download Section PDF Listen +++ ++ Suspect in setting of chronic lung disease or immunocompromised host N asteroides is a branching, filamentous gram-positive bacterium that is weakly acid-fast Identification is made by culture Chest radiograph May show infiltrates accompanied by pleural effusion Lesions may penetrate through the chest wall and invade the ribs Brain imaging should be considered even in absence of clinical symptoms and signs of CNS infection to rule out occult abscess + Treatment Download Section PDF Listen +++ ++ Trimethoprim-sulfamethoxazole (TMP-SMZ) For isolated primary cutaneous infections 5–10 mg/kg/day (based on TMP) as an oral or intravenous formulation For disseminated or pulmonary infections: 15 mg/kg/day (based on TMP) Resistance to TMP-SMZ is increasing and initiating treatment with two drugs should be considered while awaiting antibiotic susceptibilities in cases of disseminated or severe localized disease Alternative agents or drugs that can be given in combination with TMP-SMZ Imipenem, 500 mg intravenously every 6 hours Amikacin, 7.5 mg/kg intravenously every 12 hours Minocycline, 100–200 mg orally or intravenously twice daily Surgical procedures such as drainage and resection may be needed as adjunctive therapy for isolated cutaneous disease Response may be slow, and therapy should be continued for at least 6 mo The prognosis in systemic nocardiosis is poor when therapy is delayed