Successful treatment of disseminated nocardiosis diagnosed by metagenomic next-generation sequencing: A case report and review of literature

BACKGROUND: Nocardia paucivorans is an infrequently found bacterium with the potential to cause severe infection, with a predilection for the central nervous system, both in immunocompromised and immunocompetent individuals. Rapid etiological diagnosis of nocardiosis can facilitate timely and rational antimicrobial treatment. Metagenomic next-generation sequencing (mNGS) can improve the rate and reduce the turnaround time for the detection of Nocardia. CASE SUMMARY: A 49-year-old man was admitted to hospital with cough and hemoptysis. Imaging revealed pulmonary consolidation as well as multiple brain lesions. Nocardia asiatica and Nocardia beijingensis were rapidly detected by mNGS of bronchoalveolar lavage fluid (BALF) while bacterial culture of BALF and pathological biopsy of lung tissue were negative. In early stages, he was treated with trimethoprim-sulfamethoxazole (TMP-SMZ) and linezolid by individual dose adjustment based on serum concentrations and the adverse effects of thrombocytopenia and leukopenia. The treatment was then replaced by TMP-SMZ and ceftriaxone or minocycline. He was treated with 8 mo of parenteral and/or oral antibiotics, and obvious clinical improvement was achieved with resolution of pulmonary and brain lesions on repeat imaging. CONCLUSION: mNGS provided fast and precise pathogen detection of Nocardia. In disseminated nocardiosis, linezolid is an important alternative that can give a better outcome with the monitoring of linezolid serum concentrations and platelet count.