Table 1.

Microorganisms found in the upper and lower airways of patients with COPD

Microorganisms	Study	Disease state
Lactobacillus spp., Streptococcus spp., Pseudomonas spp., Neisseria spp., Prevotella spp., Veillonella spp.	Park et al. [52]a	Stable disease, Gold stage I–III (predominantly, I and II)
Haemophilus influenzae, Streptococcus pneumoniae, Pseudomonas aeruginosa, Klebsiella spp., Moraxella catarrhalis, Pseudomonas fluorescens	Huang et al. [28]b	Exacerbation, Gold stage I–III
Genera Afipia, Brevundimonas, Curvibacter, Moraxella, Neisseria, Undibacterium, Corynebacterium, Capnocytophaga, Leptolyngbia; Pseudomonas aeruginosa	Zakharkina et al. [53]c	Stable, Gold stage I–III
Genera Proteobacteria, Bacteroidia, Actinobacteria, Firmicutes, Streptococcus, Prevotella Fusobacterium, Neisseria, Moraxella, Haemophilus, and Acinetobacter	Cabrera-Rubio et al. [54]bc	Stable, Gold stage I–III (predominantly, I and II)
Families Acidimicrobiaceae, Burkholderiaceae, Campylobacteraceae, Caulobacteraceae, Chloroplasts, Crenotrichaceae, Desulfomicrobiaceae, Enterobacteriaceae, Helicobacteraceae Leptospiraceae, Moraxellaceae, Nitrosomonadaceae, Peptococc/Acidaminococc, Pirellulae, Piscirickettsiaceae, Pseudomonadaceae, Sphingobacteriaceae, Thermoactinomycetaceae, Thermodesulfobacteriaceae, Xanthomonadaceae, Xiphinematobacteraceae	Huang et al. [55]a	Severe exacerbation (intubated patients)

^aOropharyngeal swabs or endotracheal aspirates (upper airways)

^bSputum or bronchial aspirate (central airways)

^cBroncho-alveolar lavage (lower airways)