An eight-year experience of Nocardia infection in Italy: does immunosuppression matter?

Nocardia has always been considered a pathogen of the immunocompromised host, but recent evidence has also highlighted its role as a pathogen in the immunocompetent. We aim to assess the role of immunosuppression in the disease. We reviewed all the cases of infections due to Nocardia spp. in our center that occurred from 1 January 2012 to 30 September 2019. Patients were divided into three groups: typical immunocompromised (PLWHIV, solid organ or hematopoietic cell transplant recipients, individuals under immunosuppressive drugs), atypical immunocompromised (ongoing chronic diseases involving the lung, kidney, liver and diabetes) and immunocompetent. We identified 53 patients with an infection by Nocardia spp. Thirty-four (60.4%) of them were immunocompromised, 22 (64.7%) typical and 12 (35.3%) atypical immunocompromised. Nineteen (35.8%) were immunocompetent. The two conditions most frequently associated with infection were chronic lung disease (41.5%) and ongoing treatment with immunosuppressive drugs (33.9%). In our cohort a remarkable prevalence of nocardiosis in immunocompetent and atypical immunosuppressed patients was observed.