Diagnostic Yield of Nontuberculous Mycobacteria Testing in Patients with Chronic Lung Diseases: A Retrospective...

Obstructive lung disease (OLD), that is, chronic obstructive pulmonary disease (COPD), asthma, and pulmonary malignancies, is a common comorbidity in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). However, there are limited data on the yield of nontuberculous mycobacterial (NTM) testing in these patient groups. This study aimed to assess the prevalence of NTMs and NTM-PD in patients with OLD and/or pulmonary malignancy.

A retrospective analysis of all mycobacterial cultures obtained from respiratory samples of patients with OLD (either during exacerbation or during stable disease) and/or pulmonary malignancies referred to our center from January 2021 to January 2023 was performed. International definitions were applied to assess the NTM-PD.

NTM was isolated in 0.5% (4/834) of bronchopulmonary specimens from patients with pulmonary malignancies, 2.4% (13/553) from patients with stable OLD, and 3.5% (8/228) from patients with exacerbation of OLD. NTM-PD criteria were met in 32% (8/25) of the patients in the OLD cohort. In the OLD cohort, the likelihood of NTM isolation was higher in patients with lower BMI (p = 0.030), frequent exacerbations (p = 0.004), and use of inhaled corticosteroids (ICS) (p = 0.012). NTM-PD was more likely in patients with a lower BMI (p = 0.043) and frequent exacerbations (p = 0.023), but not in those using ICS (p = 0.482), regardless of the dose.

The yield of NTM isolation from patients with OLD and/or lung malignancy is generally low. However, routine microbiological testing for NTM from bronchopulmonary specimens and assessment of the presence of NTM-PD could be considered in patients with OLD with a low BMI and/or frequent exacerbations.