Pulmonary nocardiosis in a tertiary care hospital: 8-year experience (1999–2006)

Abstract number: 1733_219

Papaefstathiou E., Kanellopoulou M., Skarmoutsou N., Martsoukou M., Katiska P., Papafrangas E., Tsakris A.

Objectives:Pulmonary nocardiosis (PN) is a subacute or indolent pneumonia caused by aerobic actinomycetes of the genus Nocardia. The disease is difficult to diagnose and therefore its incidence is not well established. We report our experience on PN in a case study conducted in our hospital (108 pulmonary beds) during a period of eight years (1999–2006).

Methods: Sputa of all admitted patients were smeared, stained by Gram and ZN and plated in appropriate media. The identification of Nocardia species was performed by drug susceptibility patterns (MIC, E-test, Disk diffusion method) in conjunction with the profiles of conventional biochemical assays. Information was collected on demographic data, clinical details, underlying diseases and immunosuppressive therapy.

Results: Thenty-nine patients with PN were studied (17 males and 12 females; mean age 52 y). Pathogens were N. asteroides I, II, VI (22/29), N. farcinica (6/29) and N. transvalensis complex (1/29). Underlying diseases included haematological and other malignancies (11 cases), cystic fibrosis (10 cases), COPD (3 cases), multiple sclerosis (2 cases), diabetes mellitus (3 cases). Diabetes mellitus was concomitant underlying disease in cystic fibrosis (2 cases) and haematological malignancies (3 cases). Seven patients had received steroid treatment. Therapy with TMP/SMX (20/29) or with the combination of imipenem and amikacin (9/29) was given to the patients for 2 to 6 months. In all but seven cystic fibrosis patients, treatment resulted in microbiological eradication of the pathogen.

Conclusion: PN is an infrequent infection that mainly affects immunocompromised patients. In our study, several Nocardia species were identified among patients with various predisposing diseases. To our experience direct Gram-stain in sputum smears was found useful to drive the diagnosis of PN, particularly in patients with underlying diseases and a clinical suspicious of the disease.