Clinical characteristics and outcomes of nocardiosis: A retrospective analysis of 44 cases

Abstract

Objective

The aim of this study was to characterize the clinical features of nocardiosis and to enhance understanding of its diagnostic and therapeutic challenges.

Methods

A retrospective review was conducted on the clinical records of 44 patients diagnosed with nocardiosis between January 2018 and December 2020. Demographic data, underlying conditions, clinical manifestations, laboratory and imaging findings, microbiological results, and treatment outcomes were analyzed.

Results

Of the 44 cases, pulmonary infection was identified in 28 cases, disseminated infection in 13 cases, and extrapulmonary single-organ infection in 3 cases. Comorbid conditions were present in 40 patients, most commonly bronchiectasis, diabetes mellitus, nephropathies, and connective tissue disorders. Thirteen patients had a history of long-term glucocorticoid or immunosuppressive therapy. The predominant symptoms included cough, sputum production, and fever, accompanied by elevated white blood cell counts, neutrophil percentages, C-reactive protein, and procalcitonin levels. Pulmonary imaging commonly revealed patchy, nodular, or mass-like opacities, bronchiectasis, and cavitary lesions. Weakly acid-fast staining yielded positive results in 32 cases. The isolated pathogens primarily included Nocardia asteroides, Nocardia farcinica, and Nocardia cyriacigeorgica. Clinical improvement was observed in 37 patients following treatment, while 7 died.

Conclusion

Nocardiosis predominantly affects the lungs, with approximately one-third of cases progressing to disseminated infection. This condition frequently affects patients with comorbidities, particularly those receiving glucocorticoids or immunosuppressants. Although clinical manifestations are nonspecific, weakly acid-fast staining demonstrates high diagnostic utility and plays a valuable role in early identification.