Pulmonary nocardiosis: risk factors, clinical features, diagnosis and prognosis

Pulmonary infection by Nocardia spp. has been recognized for the past 100 years. The number of cases of pulmonary nocardiosis reported in the literature is increasing, and in some cases, a diagnosis is reached even postmortem. This increase is partly due to the growing number of patients with depressed cellular immunity. The diagnosis of this infection, which has a high rate of mortality, is usually delayed, due to a nonspecific clinical-radiological presentation and the difficulties in cultivating the bacteria. This review analyzes the current situation, in order to better understand this infection and enhance awareness and clinical suspicion that would lead to further specific microbiological studies and treatment.

The number of case series in the literature is increasing. This development may be due to an absolute increase in the number of immunocompromised patients, but also to improvements in laboratory techniques and molecular methods to detect nocardiosis.

It is important to keep in mind, and suspect the presence of pulmonary nocardiosis in the immunodepressed patients with clinical pulmonary infection. Furthermore, the laboratory should be notified when Nocardia is suspected in a clinical specimen so that measures can be taken to optimize recognition and recovery of the organism.