Pulmonary nocardiosis: a comparative analysis of Nocardia asteroides and non-asteroides species.

Our study compares the risk factors, clinical presentations and outcomes of pulmonary infections caused by Nocardia asteroides and non-asteroides species. We performed a retrospective cohort study comparing pulmonary infections by both species in patients presenting to a tertiary care hospital in Karachi, Pakistan. Forty-one patients were identified with pulmonary nocardiosis, with 58.5% belonging to the N. asteroids complex. The most common clinical findings were fever and a cough for both groups, with lobar infiltrates being the most common finding on chest radiographs. In vitro testing showed a sensitivity of all species to trimethoprim-sulfamethoxazole (TMP-SMZ), aminoglycosides, ceftriaxone and imipenem. The majority of the patients were treated with TMP-SMZ in combination with other drugs. The results of our study suggest that there is no significant difference in the risk factors, presentations and outcomes of pulmonary infections by N. asteroides and non-asteroides species. Immunocompromised patients are more likely to have unfavorable outcomes.