Tracheobronchial invasion by nontuberculous mycobacteria: a rare but overlooked clinical manifestation—a multicenter retrospective analysis

Abstract

Background Nontuberculous mycobacteria (NTM) can disseminate and infect various organs throughout the body. However, whether NTM can infect tracheobronchial tissue is rarely reported. This study aimed to address the knowledge gap regarding the epidemiological, demographic, and clinical characteristics of patients with tracheobronchial NTM infection. Methods In this multicenter retrospective cohort study, clinical, demographic, microbiological, and radiological data from hospitalized patients with tracheobronchial NTM infections from January 2015 to May 2025 were collected and analyzed descriptively. Results Twenty-nine patients (2.3%) were included, and all the patients presented with disseminated NTM infection. Seventeen patients had comorbidities, including 5 with acquired immunodeficiency syndrome and 1 with anti-interferon-γ autoantibody syndrome. Median diagnostic delay was 130 days, and 89.7% of the patients were initially misdiagnosed with tuberculosis or malignancy. The most common symptoms were cough, expectoration, anemia, fever, weight loss, skin lesions, and bone pain. Chest CT revealed nodules, patchy opacities, mass-like shadows, and bronchial stenosis, with or without hilar/mediastinal lymphadenopathy, whereas osteolytic bone destruction was evident in 11 patients. The most common features of bronchoscopy were intraluminal masses/neoplasms/nodules. Metagenomic next-generation sequencing (mNGS) of BALF (n=12) demonstrated 100% positivity, outperforming BALF culture (46.2%, 12/26) and sputum culture (39.3%, 11/28). Mycobacterium colombiense accounted for 24.1% of cases. With respect to therapeutic management, 27 patients received systemic antimicrobial therapy, while 2 did not receive specific anti-N™ treatment. One patient underwent combined endoscopic resection. Overall, 23 patients (79.3%) achieved improvement or cure, 5 showed disease progression, 1 experienced relapse, and 1 died. Conclusions Tracheobronchial NTM infection is rare but clinically significant, often occurring in the context of disseminated disease with pulmonary involvement. Immunocompromised hosts, particularly those with AIDS or anti–IFN-γ autoantibody syndrome, are highly susceptible. Bronchoscopy typically reveals mass lesions causing luminal stenosis or occlusion. In this cohort, M. colombiense was the most frequently isolated NTM species. Early bronchoscopy, mNGS-based pathogen detection, and timely systemic or endoscopic intervention should be considered to prevent irreversible airway stenosis. Further studies are needed to validate optimal treatment strategies. Clinical Trial Registration https://www.ClinicalTrials.gov, identifier NCT07377864.