The purpose of the study is to identify the genetic closeness of NTM derived from patients living together and from their surrounding environment and to trace the temporal relationship between them.

After NTM isolation is done by using culture, from patients' sputum/bronchoscopic samples and their environmental samples, whole genome sequencing (WGS) will be conducted for all NTM isolates. Phylogenetic analysis will be performed based on single nucleotide polymorphism (SNP) on each NTM.

Inclusion Criteria:

• The adult over 18 years of age
• The patient who have respiratory symptoms consistent with NTM, such as a chronic cough, sputum, and hemoptysis, who have NTM-positive findings on CT, and who have NTM identification in two or more sputum cultures or in one or more bronchoscopic/tissue culture. (2007 ATS/IDSA guideline)
• Pairs of patients living in the same household since diagnosis on NTM lung disease
• Consent to a collection of environmental samples from the patient's residence.

Exclusion Criteria:

• If the patient does not agree or withdraw.

Among the patients visiting Seoul National University Hospital outpatient clinic, pairs of adult NTM lung disease patients who living together at the time of diagnosis were enrolled.