Pulmonary Nocardiosis in Immunocompetent Patients: A Report of Four Cases from a Tertiary Care Centre

Pulmonary nocardiosis (PN) is an infrequent and severe infection due to Nocardia spp. It is more common in immunosuppressed individual. The aim of this study was to evaluate the clinical features, evolution and prognosis of PN in immuno-competent hosts. The study group comprised 4 consecutive immuno-competent patients with pulmonary nocardiosis acquired in a community setting, diagnosed and followed in a tertiary care hospital. Chronic obstructive pulmonary disease (COPD) and pulmonary tuberculosis were the underlying diseases. Two patients had received anti-tubercular treatment before isolation of Nocardia spp. Clinical course was chronic and diagnosis was delayed 2 weeks or more in two out of four patients. Lobar or multilobar condensation was the most frequent radiographic pattern. The disease remained localized in the lung in all the four cases, with a trend toward chronicity in one with bronchiectasis. The following conclusions were reached : (1) In our geographical setting Nocardia presents as a subacute or chronic pulmonary infection, mainly outside the hospital. (2) Pulmonary nocardiosis is difficult to diagnose, diagnosis is frequently delayed and a high level of suspicion is, thus, required in patients with underlying diseases e.g. COPD, pulmonary tuberculosis. (3) Diagnosis requires a high clinical suspicion, and can be made on the basis of a microbiological investigation of sputum or bronchoalveolar lavage. (4) The treatment of choice for this infection includes cotrimoxazole but some Nocardia spp. may show resistance to this drug.