Naito K, Noguchi S, Yatera K, et al. - Via this study, researchers sought to determine the utility of clone library analysis of BAL fluid (BALF) for detection of nontuberculous Mycobacterium (NTM) phylotypes, including multiple NTM phylotypes, in pulmonary NTM infections. From 120 patients with suspected pulmonary NTM infections, BALF samples were obtained and were retrospectively evaluated using the mycobacterial culture and clone library methods. According to results of mycobacterial culture, 55 (45.8%) patients were diagnosed as NTM positive, and the clone library method suggested 52 patients as NTM positive. Moreover, 45 (86.5%) and seven (13.5%) patients displayed a single phylotype (mono-phylotype group) and multiple phylotypes of NTM (multi-phylotype group), respectively. Findings suggest a possible correlation of coinfection multiple phylotypes with adverse clinical findings. Further, NTM lung infection may be diagnosed within 1 year of the initial sample collection among patients who test positive for NTM genes but negative for mycobacterial culture. Further follow-up of these patients may aid in early identification of NTM species.