[Fatal nontuberculous mycobacterial lung disease caused by Mycobacterium kyorinense: a case report with five years of follow-up].

An 85-year-old man with dementia first visited our hospital 5 years ago, complaining of hemoptysis. He was hospitalized 2 years later owing to fever, cough, and dyspnea. A chest computed tomography scan showed infiltration with a cavity in the left upper lobe. He was diagnosed with nontuberculous mycobacterial lung infection on the basis of the presence of acid-fast bacilli in the sputum and repeated bronchoalveolar lavage specimens; however, we were unable to identify the isolate by DNA-DNA hybridization. Although his general condition had slightly improved after treatment initiation, intermittent chemotherapy owing to the adverse effects of the drugs and dementia led to rapid disease progression and death. After his death, the isolated mycobacterium was identified as Mycobacterium kyorinense by sequence analysis of the hsp 65 and rpoB genes.