Chronic infection with non-tuberculous mycobacteria in patients with non-CF bronchiectasis: Comparison with other pathogens

Abstract

IntroductionThe aim of this study is to compare characteristics of non-cystic fibrosis bronchiectasis (NCFBE) patients with chronic infections with non-tuberculous mycobacteria (NTM) versus those with Pseudomonas aeruginosa or other colonizations. MethodsThis was an observational, perspective study of consecutive NCFBE adult patients attending the outpatient bronchiectasis clinic at the San Gerardo Hospital in Monza, Italy, during 2012 and 2013. Patients with a chronic infection were included in the study and divided into three groups: those with NTM (Group A); those with P. aeruginosa (Group B); and those with other pathogens (Group C). Patients with both NTM and another pathogen were included in Group A. Comparison among the three study groups was performed using X2 or Fisher exact test for categorical variables or Kruskal–Wallis or Mann–Whitney test for continuous variables. ResultsA total of 146 patients (median age 67years, 40% males) were enrolled: 19 belonged to Group A, 34 to Group B and 93 to Group C. Within group A, 6 patients had only NTM isolation, 7 patients had NTM and P. aeruginosa co-infection and 6 patients had NTM plus another pathogen. The most common isolated pathogens among NTM was Mycobacterium avium complex (15 patients, 79%). A total of 4 patients (21%) with NTM were on active treatment. Patients affected by NTM pulmonary infection had a significantly less severe clinical, functional and radiological involvement compared with patients colonized by P. aeruginosa, see Table.Group A (NTM)n=19Group B (P. aeruginosa)n=34Group C (Others)n=93p Value∗p Value#p Value+Age (years), median (IQR)70 (64–75)74 (67–79)66 (53–72)0.0010.1720.050Male, n (%)8 (42)15 (44)36 (33)0.660––BMI, median (IQR)22 (19–26)24 (21–25)24 (21–27)0.352––BSI, median (IQR)5 (4–9)12 (8.5–16)5 (3–7)0.0010.0010.090Bhalla score, median (IQR)21 (15–34)36 (30.5–40.5)16 (10.5–21.5)0.0010.0160.076Idiopathic etiology, n (%)8 (42)11 (32)37 (40)0.721––Post-infective etiology, n (%)8 (42)16 (47)29 (31)0.244––Exacerbations/y, median (IQR)1 (0–2)2 (1.5–3.5)2 (1–2)0.0400.0240.132FEV1%, median (IQR)85 (59.75–109.5)58.5 (48.25–74)84 (62–102)0.0020.0100.857FVC%, median (IQR)94.5 (70–109.75)65 (56–81.5)88 (69.5–101.5)0.0030.0030.270∗Among the three groups: #Group A vs. Group B; +Group A vs. Group C; BMI: Body mass index; BSI: bronchiectasis severity index; y: year. ConclusionsColonization with P. aeruginosa seems to have the highest impact on the clinical, functional and radiological status of patients with NCFBE. No specific characteristics may help to identify NTM versus other pathogen colonizations. Thus, diagnostics for atypical mycobacteria should be performed on all patients with NCFBE, as suggested by recent international guidelines.