Clinical Predictors of Nontuberculous Mycobacteria Lung Disease and Coisolates of Potential Pathogenic Microorganisms in Noncystic Fibrosis Bronchiectasis

Abstract

Background: In bronchiectasis, nontuberculous mycobacteria (NTM) lung disease (NTM-LD) is a well-known coexisting infection. However, microorganism coisolates and clinical NTM-LD predictors are poorly studied.

Methods: Patients with bronchiectasis diagnosed by means of computed tomography between January 2017 and June 2020 were screened, using the date of computed tomography as the index date. Those with a major bronchiectasis diagnosis in ≥2 follow-up visits after the index date were enrolled in the study, and NTM-LD occurrence and its association with pneumonia and hospitalization within 1 year were analyzed.

Results: Of the 2717 participants, 79 (2.9%) had NTM-LD diagnosed. The factors associated with NTM-LD included hemoptysis, postinfectious bronchiectasis, a tree-in-bud score ≥2, a modified Reiff score ≥4, and chronic obstructive pulmonary disease (adjusted odds ratios, 1.80, 2.36, 1.78, 2.95, and 0.51, respectively). Compared with patients in the non-NTM group, those with NTM-LD had higher rates of hospitalization (15.9% vs 32.9%; P < .001) and pneumonia (9.8% vs 20.3%; P = .003). Pseudomonas aeruginosa was the most common microorganism in those with NTM-LD and those in the non-NTM group (10.1% vs 7.8%; P = .40). However, compared with those in the non-NTM group, Acinetobacter baumannii and Escherichia coli were more prevalent in patients with NTM-LD (0.7% vs 3.8% [P = .03%] and 1.0% vs 3.8% [P = .05], respectively).

Conclusions: Postinfectious bronchiectasis with hemoptysis, higher radiological involvement, and a tree-in-bud pattern were associated with NTM-LD risk. The rate of A baumannii and E coli coisolation was higher in bronchiectasis populations with NTM-LD.

Keywords: bronchiectasis; nontuberculous mycobacteria; outcome; potential pathogenic microorganisms; risk factors.

Figure 1.

Percentage of nontuberculous mycobacteria (NTM) species in individuals with NTM–lung disease (LD) associated with bronchiectasis. Mycobacterium abscessus complex (MABC) accounted for 43% of NTM-LD cases, followed by Mycobacterium avium complex (MAC) (38%), Mycobacterium kansasii (MK) (12.7%), Mycobacterium gordonae (2.5%), and Mycobacterium fortuitum (1.3%).

Figure 2.

Receiver operating curve of risk factors associated with nontuberculous mycobacteria lung disease (NTM-LD). The risk factors for NTM-LD were identified as hemoptysis, postinfectious bronchiectasis, radiological tree-in-bud score ≥2, and modified Reiff score ≥4 through multivariable analysis. The area under the receiver operating curve was 0.709 (95% confidence interval, .652–.766; P < .001).

Figure 3.

Outcomes of bronchiectasis comparing the nontuberculous mycobacteria (NTM) lung disease (NTM-LD) and non-NTM groups. A, Rates of pneumonia and hospitalization within 1 year. B, Kaplan-Meier 3-year survival curve comparing NTM-LD and non-NTM group. Patients in the NTM-LD group had significantly higher rates of pneumonia and hospitalization than those in the non-NTM group. The mortality rate at 3 years for individuals with NTM-LD was 6.3%, slightly higher than the 2.8% in those without NTM isolates.

Figure 4.

Coisolates of potential pathogenic microorganisms in individuals with nontuberculous mycobacteria (NTM) lung disease (LD) and those without any NTM isolation. Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii were the 4 most commonly coisolated bacteria in NTM-LD. There was no significant difference in the presence of P aeruginosa between NTM-LD and non-NTM groups, but E coli and A baumannii occurred more frequently in the NTM-LD group. Abbreviations: H influenzae, Haemophilus influenzae; S aureus, Staphylococcus aureus; S pneumoniae, Streptococcus pneumoniae.