Nocardiosis in Immunocompromised Hosts: A Retrospective, Single‐Center Analysis of Clinical and Microbiological Determinants of Central Nervous System Involvement

BACKGROUND Immunocompromised patients are at risk of disseminated nocardiosis, which can involve the central nervous system. The factors mediating dissemination to the central nervous system in this patient population have not been fully characterized. This study aimed to identify patient and pathogen-related variables associated with a higher risk of central nervous system infection among immunocompromised patients with nocardiosis.

METHODS Retrospective single-center analysis of all immunocompromised patients diagnosed with nocardiosis between 2013 and 2024. Patients without brain imaging were excluded from the analysis. A case-control analysis was conducted to compare patients with central nervous system involvement (cases) and those without (controls), examining demographic, immunosuppression-related, and pathogen-related variables through univariate analysis.

RESULTS A total of 54 patients were included in the study. The most common type of immunosuppression was solid organ transplantation (39%). The prevalence of central nervous system involvement was 30%. In univariate analysis, white, non-Hispanic patients and patients with bronchiectasis had lower odds of central nervous system involvement. In contrast, patients infected with Nocardia farcinica had higher odds of central nervous system involvement.

CONCLUSION Immunocompromised patients with nocardiosis who had brain involvement did not differ significantly from those without brain involvement in terms of immunosuppression-related factors. Instead, this difference appears to be explained by differences in the virulence of Nocardia species, particularly N. farcinica.