Bronchial Brushing And Diagnosis Of Pulmonary Nontuberculous Mycobacteria Infection

Background: The optimal bronchoscopy procedure for diagnosis of pulmonary nontuberculous mycobacteria (NTM) infection is unclear. Objective: This study investigated the usefulness of bronchial brushing in bronchoscopy for diagnosis of pulmonary NTM infection in patients with suspected NTM lung disease and nodular bronchiectasis on chest computed tomography (CT) images. Methods: Bronchoscopy was prospectively performed for 69 patients with clinically suspected pulmonary NTM infection on chest CT from December 2017 through December 2019. Before and after bronchial brushing, bronchial washing was performed with 20 or 40 mL of normal sterile saline at the same segmental or subsegmental bronchi. Before and after bronchial brushing, samples of the washing fluid (pre- and postbrushing samples) and brush deposits (brush samples) were obtained and cultured separately. Results: NTM was detected in 37 of the 69 (53.6%) patients (Mycobacterium avium in 27, Mycobacterium intracellulare in 7, M. abscessus in 2, and M. kansasii in 2). NTM was detected in 34 (49.3%) prebrushing samples, in 27 (39.1%) postbrushing samples, and in 20 (29.0%) brush samples from the 69 patients. In 2 (2.9%) patients, NTM was detected only in postbrushing samples; in 1 (1.4%) patient, NTM was detected only in a brush sample. As compared with bronchial washing only, additional bronchial brushing increased the NTM culture-positive rate by 4.3% (3/69). Bronchial brushing caused bleeding, requiring hemostasis in 5 (7.2%) patients. Conclusion: Additional bronchial brushing increased the NTM culture-positive rate by only 4.3% (3/69), as compared with bronchial washing alone. Thus, the usefulness of brushing appears to be limited.