Three cases of pulmonary infection caused by Nocardia farcinica and literature review

Objective To improve the understanding of clinical features, imaging features, treatment and prognosis of pulmonary infection caused by Nocardia farcinica and the level of diagnosis and treatment. Methods Three cases of pulmonary infection caused by Nocardia farcinica diagnosed and treated in Xuanwu Hospital, Capital Medical University were reported and disscussed in combination with relevant literatures. Results Of the three patients, two had connective tissue disease and used glucocorticoid and immunosuppressive agents and one was previously healthy.The two relatively young patients presented with chronic course and one elderly patient presented with progressive exacerbation of acute course within 2 weeks.All the three patients had cough and expectoration with two cases accompanied by fever.CT scan of the three patients showed multiple plaques or patchy exudation in the lungs with thick-walled cavities in two cases.Three patients were given trimethoprim-sulfamethoxazole based combination therapy and the symptoms were relieved. Conclusions Most patients with pulmonary infection caused by Nocardia farcinica have immunodeficiency.Clinical features and imaging lack specificity.Pulmonary nocardiosis caused by Nocardia farcinica is easy to be misdiagnosed as tuberculosis or fungal infection.Most of the patients with compound sulfamethoxazole based combination therapy have good prognosis.