A case of colonization and recurrence of Nocardia pseudobrasiliensispneumonia in an immunocompromised patient

Background: Nocardiosis is a rare opportunistic disease that affects mainly patients with deficient cell-mediated immunity. Furthermore, otential pulmonary disease could be considered to be risk factors for infection and colonization by pulmonary Nocardia.Case reprensent: Here we present a case of Nocardia pseudobrasiliensis co-infection in a male with bronchiectasis. Pathogens were detected by metagenomics nextgeneration sequencing (mNGS) of bronchoalveolar lavage fluid. The patient was diagnosed with mixed pulmonary infection by multiple pathogens. With a combination of antibiotics, the patient was finally discharged. However, Nocardia persists in the lungs and cause recurrent infections.Conclusion: When refractory mixed lung infections are encountered, mNGS can be used for early diagnosis. Meanwhile, this case suggests that correcting risk factors and adequate treatment with sensitive antibiotics are important for the management of continuous presence or recurrence of Nocardia infection.