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

Mateja Jankovic Makek,1,2 Ena Tolic,2 Christoph Lange,3– 6 Matea Zvonar,2 Dora Darapi MaruÅ¡ić,2 Ivana Marekovic,1,7 Sonja Badovinac,2 Goran Glodic,2 Kristijan Marcic,1 Nika Zielinski,3– 5 Maja Reimann3– 5 1School of Medicine, University of Zagreb, Zagreb, Croatia; 2Department for Respiratory Diseases, University Hospital Centre Zagreb, Zagreb, Croatia; 3Clinical Infectious Diseases, Research Centre Borstel, Borstel, Germany; 4German Centre for Infection Research (DZIF), Partner Site Hamburg-Lübeck-Borstel-Riems, Borstel, Germany; 5Respiratory Medicine & International Health, University of Lübeck, Lübeck, Germany; 6Department of Paediatrics, Texas Children’s Hospital; The Global Tuberculosis Program; Immigrant and Global Health, Baylor College of Medicine, Houston, TX, USA; 7Department for Microbiology, University Hospital Centre Zagreb, Zagreb, CroatiaCorrespondence: Maja Reimann, Clinical Infectious Diseases, Research Centre Borstel, Borstel, Germany, Email [email protected]: 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.Methods: 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.Results: 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.Conclusion: 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. The infographic presents data on mycobacterial cultures from 1615 patient episodes involving 1538 patients. It categorizes episodes into lung malignancy (834 episodes, 819 patients), stable OLD (553 episodes, 525 patients) and OLD in exacerbation (228 episodes, 222 patients). Total NTM isolations are 25 out of 1615 (1.5 percent), with confirmed NTM-PD in 8 cases (32 percent), all in the OLD group. The NTM isolation rate is shown in a bar graph: lung malignancy (4/834, 0.48 percent), stable OLD (13/553, 2.4 percent) and exacerbated OLD (8/228, 3.5 percent). In the OLD cohort, NTM isolation is more likely in patients with lower BMI (p=0.03), frequent exacerbators (p=0.0004) and those on inhaled corticosteroid therapy (p=0.043). NTM-PD is more likely in patients with lower BMI (p=0.043) and frequent exacerbators (p=0.023).Infographic on NTM isolation rates in lung conditions with patient data and risk factors.Keywords: screening, atypical mycobacteria, chronic obstructive lung disease, asthma, lung cancer