The First Case of Mycobacterium interjectum Pulmonary Disease in Japan

We herein report a case of Mycobacterium interjectum pulmonary disease (M. interjectum-PD) that improved considerably after azithromycin (AZM), rifampicin (RFP), and ethambutol (EB) therapy. A 69-year-old woman, managed locally for suspected NTM-PD based on chest computed tomography (CT) findings was referred to our hospital for worsening productive cough six years after the initial diagnosis. High-resolution chest CT showed right middle and left lower lobe bronchiectasis with middle and centrilobular nodules. Bronchial washing and sputum culture yielded M. interjectum. Treatment with AZM, RFP, and EB resulted in sputum culture conversion, and the chest CT findings subsequently improved. This is the first reported case of M. interjectum-PD in Japan.