Pulmonary infection caused by Nocardia cyriacigeorgica and influenza A virus coinfection in an immunocompetent patient: A case report

Rationale

Pulmonary nocardiosis (PN) is an opportunistic infection caused by Nocardia species. It is characterized by a lack of specificity in both clinical symptoms and imaging findings. Most cases occur in individuals with compromised immune systems or underlying pulmonary diseases. In contrast, our patient did not present with any of these risk factors. Patient concerns: A 60-year-old immunocompetent male was admitted with a 5-month history of recurrent cough and expectoration. His respiratory symptoms worsened, and he developed a fever 9 days prior to hospitalization. Diagnoses: Nocardia cyriacigeorgica was identified in the sputum culture, as well as in the targeted next-generation sequencing and culture of the bronchoalveolar lavage fluid, while influenza A virus was detected by nucleic acid detection.