Mycobacterial Diseases O-004 : Usefulness of Post-bronchoscopy Sputum Culture for the Diagnosis of Nontuberculous Mycobacterial Pulmonary Disease

Background Bronchoscopy is recommended for suspected non-tuberculous mycobacteria pulmonary disease (NTM-PD) if sputum culture Results are consistently negative or adequate sputum samples cannot be obtained. The aim of this study is to assess the role of post-bronchoscopy sputum in improving diagnostic accuracy for patients with suspected NTM-PD who underwent bronchoscopy. Methods Patients with suspected NTM-PD who underwent bronchoscopy for diagnosis from January 1st, 2017 to June 30th, 2020 at Seoul National University Hospital were included for analysis. Patients were classified into the sputum culture negative group or the scanty sputum group. Results of mycobacterial culture from bronchial washing specimen and post-bronchoscopy sputum were compared between two groups. Results 141 patients were included in the analysis. 39 patients were classified into the sputum culture negative group and 102 patients into the scanty sputum group. NTM was cultured from bronchial washing specimen in 38.3% (54/141) of all patients; 30.7% (12/39) of patients in sputum culture negative group and 41.2% (42/102) of patients in scanty sputum group (P=0.345). NTM was exclusively cultured from post-bronchoscopy sputum in 3.5% (5/141) patients; 7.7% (3/39) patients in sputum culture negative group and 2.0% (2/102) of patients in scanty sputum group (P = 0.255). Conclusions In patients with suspected NTM-PD who have negative Results from sputum NTM culture or scanty sputum, post-bronchoscopy sputum could play a minor role in improving diagnostic accuracy in NTM-PD.