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For further information, see CMDT Part 35-33: Nocardiosis
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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, Nocardia brasiliensis, and Nocardia nova
Bronchopulmonary abnormalities (eg, bronchiectasis) may predispose to colonization, but infection may not occur unless the patient is also receiving systemic corticosteroids or is otherwise immunosuppressed
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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 may involve any organ; brain abscesses and subcutaneous nodules are most frequent
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N asteroides is a branching, filamentous gram-positive bacterium that is weakly acid-fast
Identification is made by culture
Chest radiograph
Brain imaging is recommended even in absence of clinical symptoms and signs of CNS infection to rule out occult abscess
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Trimethoprim-sulfamethoxazole (TMP-SMZ)
For isolated cutaneous infections: 5–10 mg/kg/day (based on TMP) orally or intravenously
For disseminated or pulmonary infections: 15 mg/kg/day (based on TMP), often in combination with other antimicrobials
Resistance to TMP-SMZ has increased, consider initiating treatment with two drugs 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
Ceftriaxone, 2 g intravenously every 12 hours
Linezolid, 600 mg intravenously or orally every 12 hours
Minocycline, 100–200 mg orally or intravenously twice daily
Brain abscesses or severe pneumonia should be initially treated with combination therapy
Surgical procedures such as drainage and resection may be needed as adjunctive therapy
Response may be slow, and therapy should be continued for at least 6–12 months
The prognosis in systemic nocardiosis is poor when therapy is delayed