Chronic Obstructive Pulmonary Disease (COPD) has become the third leading cause of death all over the world. Frequent acute exacerbations can even increase the mortality of COPD. Therefore, preventing the acute exacerbation of COPD (AECOPD) might improve prognosis.~About 74% of stable COPD patients had underlying pathogen colonization, mainly Gram-negative bacteria, in lower respiratory tract (LRT). Bacterial colonization can damage the airways of COPD patients, leading to disease progression. Further disruption of airway defense mechanisms promotes the adhesion and growth of bacteria in reverse. Eventually, a vicious circle is formed between LRT bacterial colonization and the progression of COPD. Thus, moderate to severe COPD patients were more likely to have LRT colonization, and patients with higher load of LRT bacterial colonization tended to have more frequent acute exacerbations. Decolonization of LRT bacteria may be able to control the progression of COPD and prevent AECOPD through breaking the vicious circle.~Instead of proving that long-term use of antibiotics in stable stage of COPD can prevent AECOPD, previous clinical trials have found that it can lead to the development of severe adverse reactions and the growth of LRT drug-resistant bacteria. It is probably because the main colonized LTR bacteria were not sensitive to those investigational drugs. Additionally, drugs were delivered systematically in those previous studies. Theoretically, inhalation administration can deliver the drug directly to the lungs, leading to higher drug concentrations in the lungs and less occurrence of systemic adverse reactions. Therefore, inhalation administration can well make up for the deficiencies of systematic administration. Studies on cystic fibrosis and bronchiectasis have yielded promising results of the safety and effectiveness of inhaled antibiotics for LRT bacterial decolonization. As COPD has similar manifestations to the two diseases, the promising results indicated the feasibility of decolonization of LRT bacteria to prevent AECOPD.~Previously, a multicentral clinical trial conducted by our research team preliminarily investigated whether nebulized Amikacin combined with conventional therapy could prevent AECOPD and disease progression of COPD. However, whether decolonization of LRT bacteria plays a role in these process remains unknown. The main purpose of this research is to confirm the prophylactic effect of decolonization of LRT bacteria on AECOPD and establish a novel prophylactic therapy for sable COPD.
The underlying bacterial colonization in lower respiratory tract (LRT) of COPD patients may be related to acute exacerbation of COPD (AECOPD) and disease progression. However, there is a lack of strong evidence on the effect of LRT bacterial decolonization on COPD. This study was designed to confirm the prophylactic effect of decolonization of LRT bacteria on AECOPD and establish a novel prophylactic therapy for sable COPD.