Nontuberculous mycobacteria (NTM), not like Mycobacterium tuberculosis, is ubiquitous in environment including soil and water. Therefore, NTM pulmonary infection is not diagnosed only by microbiology of respiratory specimen but also clinical and radiographical findings.(1) Due to airway NTM colonization is not uncommon in sputum, diagnosis of pulmonary NTM infection is a big challenge in clinical practice. Especially NTM burden is increasing in recent literature.(2,3) Besides, the short-term mortality is reported higher in patients with NTM infection in medical ICU by Shu et al.(4) Early diagnosis and then treatment of NTM infection become important though NTM infection is considered as indolent process before.(1) Inflammatory marker in the patients with NTM being isolated from respiratory specimens is an indicator for differentiating true infection from colonization.(5,6) Those inflammatory factors might include blood white count, C-reactive protein, cytokines, procalcitonin , trigger receptor expressed on myeloid cell-1 (TREM-1) and Toll-like receptor-2. We therefore conduct this prospective study for analyzing