title: Relevance of lower airway bacterial colonization, airway inflammation, and pulmonary function in the stable stage of chronic obstructive pulmonary disease.
abstract: The objective of this investigation was to verify the hypothesis that the presence of lower airway bacterial colonization (LABC) can be a stimulating factor of airway inflammation, more frequent exacerbation, and impact on pulmonary function, independent of current tobacco smoking in the stable phase of chronic obstructive pulmonary disease (COPD). A total of 46 ex-smokers with moderate to severe COPD, 19 healthy non-smokers, and 17 ex-smokers without COPD were included in this study. Their sputum specimens were collected at the first baseline visit and at the second visit after a follow-up of one year. The samples were analyzed for bacterial growth by culture, and the levels of interleukin (IL)-6, IL-8, and tumor necrosis factor alpha (TNF-α) were measured by enzyme-linked immunosorbent assay (ELISA). The frequencies of exacerbations and pulmonary function were compared at visit 2. At visit 1, 37.0% (17/46) were found to have LABC with bacterial loads ≥10⁶ CFU/ml in their sputum specimens. Haemophilus influenzae was the predominant pathogenic organism isolated. IL-8, IL-6, and TNF-α in these patients' sputum were significantly higher than those without LABC (p < 0.05). It was the presence of LABC that contributed to the significantly elevated IL-8 and IL-6 at the 1-year period (p < 0.05). LABC was also associated with significantly increased frequencies of exacerbations and declined forced expiratory volume in 1 s (FEV₁) (p < 0.05). LABC was documented in a subpopulation of stable COPD patients; it may be responsible for the deterioration of pulmonary function of COPD patients by promoting airway inflammation and/or increased frequency of exacerbations independently of tobacco smoking.
authors: Department of Respiratory Medicine, The First People's Hospital Affiliated to Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, China.
authors: M
authors: M
authors: Zhang
authors: Q
authors: Q
authors: Li
authors: X-Y
authors: XY
authors: Zhang
authors: X
authors: X
authors: Ding
authors: D
authors: D
authors: Zhu
authors: X
authors: X
authors: Zhou
mesh_terms: D000368:Aged; D058491:Bacterial Load; D005260:Female; D006193:Haemophilus influenzae / Q000302:isolation & purification; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000382:microbiology*; D015850:Interleukin-6 / Q000096:biosynthesis; D016209:Interleukin-8 / Q000096:biosynthesis; D008168:Lung / Q000276:immunology / Q000382:microbiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000276:immunology / Q000382:microbiology / Q000503:physiopathology*; D012129:Respiratory Function Tests; D013183:Sputum / Q000276:immunology / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D015850:Interleukin-6; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha