Pulmonary Nocardiosis: Clinical Experience in Ten Cases

Abstract

Background: Pulmonary nocardiosis is an infrequent infection whose incidence seems to be increasing due to a higher degree of clinical suspicion and the increasing number of immunosuppressive factors. Objective: To study the predisposing factors, clinical characteristics, diagnostic procedures, treatment and progress of pulmonary nocardiosis (PN). Methods: Review of 10 patients (9 male, 1 female, mean age 61) with PN in a 600-bed teaching hospital, diagnosed from 1992 to 1999. Results: Associated diseases observed were chronic obstructive pulmonary disease (COPD) in 6 patients, human immunodeficiency virus (HIV) infection in 3 and polymyalgia rheumatica in 1. Four patients had received oral corticotherapy for COPD for over a year (mean dose 13 mg/day of prednisone or equivalent). The main reason for consultation was an increase in dyspnea in the patients with COPD (6/6) and fever in those with HIV (3/3). Mean time between onset of symptoms and diagnosis was 5 weeks. In 8 patients, the infection occurred outside the hospital setting. The infection was restricted to the lung in 9/10; in the remaining case, the central nervous system (CNS) and subcutaneous tissue were affected. Lobar or multilobar consolidation was the most frequent radiographic pattern found (6/10). Sputum culture was positive when performed (8 cases). Diagnosis was made or confirmed by bronchoscopy (bronchoaspirate or protected specimen brush) in 5 patients. Germs isolated were: Nocardia asteroides (8/10), Nocardia farcinica (1/10), Nocardia otitidiscaviarum (1/10). Cotrimoxazole was the most used empirical treatment (6/10). Resolution was achieved in 5 cases. Four subjects died: 1 HIV patient with disseminated nocardiosis, and 3 COPD patients, 2 of whom had received long-term corticotherapy. Illness recurred in only 1 case, due to failure to comply with treatment. Conclusions: (1) In our geographical setting Nocardia presents as a subacute or chronic pulmonary infection, mainly outside the hospital. (2) It tends to affect only the lung. (3) Diagnosis requires a high clinical suspicion, and can be made on the basis of a sputum culture. (4) Nocardia tends to attack patients with underlying COPD, or immunodepressed patients treated with glucocorticoids, or patients with HIV infection. (5) Mortality is high in both COPD and HIV patients. (6) In our area, cotrimoxazole seems to be the most commonly prescribed treatment.

Cavitary Pulmonary Disease

“…The most common risk factor for pulmonary nocardiosis is underlying lung disease such as asthma, bronchiectasis, or chronic obstructive pulmonary disease (105,159,301). Persons with systemic immunodeficiencies associated with cancer chemotherapy, human immunodeficiency virus, organ transplant, and long-term corticosteroid use are also at risk for pulmonary Nocardia infection, but approximately 15% of patients will have no underlying disorder (159,234). Disease onset is usually subacute, and symptoms including fever, cough, and dyspnea are usually present for several days to several weeks before diagnosis (244).…”

“…Cavitation may be more frequently observed among persons with advanced human immunodeficiency virus than among other hosts (36). Nocardia infection may be associated with mortality rates as high as 30 to 40%, particularly among hosts with severe immune compromise (234,244).…”

Phylogeny of the Genus Nocardia Based on Reassessed 16S rRNA Gene Sequences Reveals Underspeciation and Division of Strains Classified as Nocardia asteroides into Three Established Species and Two Unnamed Taxons

“…Many of these can cause clinical diseases in humans and animals, including pulmonary, central nervous system, and cutaneous infections that are all diagnosed by culture and identification of the organisms (1,10,11). Identification to the genus level is well established based on chemotaxonomic characteristics, mainly on the presence of a major amount of mesodiaminopimelic acid, arabinose, galactose, and mycolic acids with 46 to 60 carbons in cell walls (13,14).…”

Multiple Cavitary Nodules Accompanied by Pulmonary Nocardiosis in a Patient with Systemic Lupus Erythematosus

“…[1,2] Although originally believed to be fungi, Nocardia are now classified as higher order bacteria and are related to actinomyces. [3] Nocardial infections can be difficult to recognize, which leads to misdiagnosis and, consequently, an underestimation of its incidence.…”

“…[8] It was also true for our patient who was male, which is similar to most of the published reports. [2,9,10] The reason for this distribution is unclear and may be related to hormonal effects on the virulence or growth of Nocardia. [11] In general, most patients presenting with nocardiosis have a certain degree of immune deficiency.…”