Nocardia spp infections among hematological patients: results of a retrospective multicenter study

OBJECTIVES: To describe the clinical characteristics and prognostic factors of hematological patients affected by Nocardia spp infections. METHODS: We retrospectively evaluated all the cases diagnosed in four Italian institutions. RESULTS: Between 2002 and 2012, 10 cases of nocardiosis were recorded. The median age of the patients was 66 years (range 24-85 years). The underlying hematological disease was a lymphoproliferative disorder in all but two patients. Eight patients (80%) showed active underlying hematological disease, relapsed or refractory in five (50%); one patient had a history of previous allogeneic bone marrow transplantation. Eight patients (80%) were on steroid therapy; lymphopenia was present in 8/10 (80%) patients. All patients showed lung involvement. Six patients were affected by disseminated nocardiosis. Three patients (30%) were nocardemic and three (30%) showed central nervous system involvement. Skin, lymph nodes, and bone were involved in one patient each. The median overall survival was 65 days. Older age, a longer period between hematological diagnosis and Nocardia spp infection, and relapsed/refractory hematological disease were associated with a worse prognosis. CONCLUSIONS: Although rare, nocardiosis should be considered in the differential diagnosis of pulmonary and central nervous system lesions among hematological patients. Lymphoproliferative disorders, prolonged steroid treatment, lymphopenia, and active hematological disease are the conditions that are worth considering as predisposing factors for the development of this disease.