Prevalence of Culture-Confirmed Tuberculosis Among Patients with Nontuberculous Mycobacterial Disease

Background: Currently, the prevalence of nontuberculous mycobacteria (NTM) strains isolated from mycobacterial cultures has been well characterized. However, the data on the prevalence of tuberculosis (TB) in patients with NTM disease remain unclear. Methods: Between January 2012 and August 2020, consecutive patients with positive mycobacterial cultures were included for analysis. The identification of Mycobacteria spp. was performed using the DNA array method or sequencing of 16S rDNA. NTM disease is diagnosed when the same infectious agent is identified in at least two sputum or is identified in sterile samples. Results: A total of 997 strains were isolated from 828 inpatients. Of them, 261 inpatients (31.5%) were diagnosed as NTM disease. The mean age of the 261 patients was 55.7 +/- 15.5 years old and 64.0% (n = 167) of them were male. The prevalence of cultureconfirmed TB patients among patients with NTM disease was estimated as 8.0% (21/261). Conclusion: TB is common in NTM disease and caution should be taken when initiating the treatment of NTM disease.