Respiratory Microbiome Alterations in Chronic obstructive pulmonary disease Pathogenesis and Therapeutic Implications

Abstract

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder characterized by persistent airflow limitation, chronic inflammation, and recurrent exacerbations. Recent advances in microbiome research have revealed that microbial dysbiosis plays a significant role in COPD pathogenesis and disease progression. Alterations in the lung microbiome are commonly associated with reduced microbial diversity and enrichment of pathogenic bacteria such as Haemophilus, Moraxella, and Pseudomonas. These microbial shifts contribute to chronic airway inflammation, immune dysregulation, tissue remodeling, and exacerbation frequency. Several studies have demonstrated that microbiome composition varies according to disease severity, anatomical location, and sample type, highlighting the complexity of respiratory microbial communities in COPD. In addition to the lung microbiome, growing evidence supports the importance of the gut–lung axis, where gut microbial alterations may influence pulmonary immune responses and systemic inflammation. Microbial metabolites and host–microbiome interactions have also emerged as potential biomarkers for disease prognosis and therapeutic response. Despite promising findings, inconsistencies among studies remain due to differences in sampling methods, patient populations, and analytical approaches. This review summarizes current knowledge regarding respiratory and gut microbiome dysbiosis in COPD, its immunological implications, associated clinical outcomes, and potential microbiome-targeted therapeutic strategies for future disease management.