[A case of acute pseudomembranous necrotizing tracheobronchitis in an adult].

This study presented a rare case of secondary <i>Staphylococcus aureus</i> (<i>S. aureus</i>) infection following influenza B virus infection, resulting in diffuse airway injury and hemorrhagic pneumonia. The patient initially underwent bronchial artery embolization (BAE) due to persistent hemoptysis refractory to conventional hemostatic therapy. Although the hemoptysis was resolved postoperatively, severe hypoxemia persisted. Bronchoscopy revealed diffuse yellow plaques with mucosal erosion and necrosis in the airways. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid identified <i>S. aureus</i> harboring the Panton-Valentine leukocidin (PVL) genes. Histopathological examination revealed severe acute inflammatory changes consistent with necrotizing airway pathology. A diagnosis of IBV-associated <i>S. aureus</i> infection leading to acute pseudomembranous necrotizing tracheobronchitis and hemorrhagic pneumonia was made. The patient responded favorably to linezolid therapy. Follow-up bronchoscopy revealed multiple granulation tissues in the airways, which were subsequently removed under endoscopic guidance. After ruling out persistent infection, the patient was treated with low-dose oral prednisone, which resulted in significant clinical improvement.