Nocardiosis: Overview, Diagnosis, and Clinical Implications
Subject Areas : Biotechnological Journal of Environmental Microbiology
1 - Department of Microbiology, Tabriz Branch, Tabriz, Iran
Keywords: Nocardia , Immunocompromised , Diagnosis , mNGS , Treatment , N.farcinica ,
Abstract :
Nocardiosis is a serious, albeit uncommon, infection caused by aerobic, gram-positive bacteria of the genus Nocardia. Ubiquitous in soil, these environmental organisms are opportunistic pathogens, primarily affecting immunocompromised individuals and causing disease in the lungs, brain, and skin. Diagnosis traditionally depends on microbiological culture and imaging, but recent advances like metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) allow for rapid and precise pathogen identification.
Effective management requires species-specific identification, as pathogens like N. farcinica (associated with brain abscesses and rare endocarditis) and N. brasiliensis (linked to cutaneous lesions) exhibit distinct virulence and antibiotic susceptibility. Trimethoprim-sulfamethoxazole is a common first-line therapy. Given that nocardiosis can mimic other diseases and requires prolonged treatment, early detection is critical to improving outcomes. Heightened clinical awareness of this opportunistic infection, coupled with the growing use of molecular diagnostics, is essential for reducing mortality, particularly among vulnerable populations.