Dynamics of the lung microbiome in intensive care patients with chronic obstructive pulmonary disease and community-acquired pneumonia.

Little is known about the composition and clinical implications of lung microbiome in patients with chronic obstructive pulmonary disease (COPD) and community-acquired pneumonia requiring invasive mechanical ventilation and intensive care unit admission. Therefore, this study aimed to explore the longitudinal changes in microbial airway composition and its variations between COPD patients with different weaning outcomes. Fifty-one endotracheal aspirate samples from 21 participants and 5 saline samples were collected as the patient and control group, respectively. Sequence analysis revealed significant increases and upward trends in the relative abundance of the Acinetobacter genus and Acinetobacter baumannii complex species in paired comparisons of sampling points and over time, respectively, in patients with failed weaning (p for trend = 0.012 and 0.012, respectively) but not in those with successful weaning (p for trend = 0.335 and 0.426, respectively). Furthermore, significant changes in the composition of the bacterial community were observed in paired comparisons of sampling points in patients with failed weaning compared with those with successful weaning. The alpha diversity did not differ between the patients with different weaning outcomes. These results further the understanding of longitudinal airway microbiome structure analysis and its clinical implications when managing critically ill patients with and without COPD.