[Pulmonary nocardiosis in immunocompetent patients: about 2 cases]

Nocardiosis is a rare but severe infection caused by bacteria of the genus nocardia, which belong to the order actinomycetales. If they can affect immunocompetent adult, nocardioses are pathologies affecting the individuals with weakened immune system. Pulmonary involvement is the most common manifestation, its correct management is based on diagnosis, which is often delayed due to non-specific symptoms and inconclusive specimens. We here report two cases of nocardiosis in immunocompetent patients. The first case concerns a 24-year old man with a history of smoking and alcoholism, hospitalized for chest pain and hemoptysis of low abundance evolving for two months, associated with the occurrence of dorsal subcutaneous fistulized abscess. Radiological assessment showed right mediastino-pulmonary tissue mass associated with adjacent costal lysis and dissemination in rights paravertebral tissues. Bacteriological sampling remained negative motivating ultrasound-guided biopsy of the lesion, which confirmed the diagnosis of nocardia infection. The second case concerns a 22-year old man with a history of pleural tuberculosis treated 8 years ago and of relapse of tuberculosis in 2011 (mediastinal abscess). He was admitted to hospital due to suspicion of relapse of tuberculosis based on chronic cough with alteration of general state and hepatosplenomegaly. Chest CT scan showed alveolar condensations with pleurisy. During his hospitalization, purulent subcutaneous swellings occurred. Bacteriological analysis of the pus confirmed the diagnosis of nocardiosis. Nocardia strains were resistant to all antibiotics except for colistin and bactrim. This study aims to highlight the clinical and radiological aspects of pulmonary nocardiosis, focusing on diagnostic and therapeutic difficulties especially in a country with a high prevalence of tuberculosis and a very low incidence of nocardiosis.