Research On The Respiratory Microecology Of Chronic Obstructive Pulmonary Disease And Its Influencing Factors

Objective To analyze and compare the basic characteristics of respiratory microecology in patients with chronic obstructive pulmonary disease(COPD)at different periods and the similarities and differences between COPD patients and healthy people,to explore factors influencing respiratory microflora in patients with acute exacerbations of chronic obstructive pulmonary disease(AECOPD),and to expand new research data for the study of respiratory microecology in COPD patients.To provide new diagnostic tools and treatment patterns.Methods A total of 30 patients with stable COPD,69 patients with acute exacerbation and 45 healthy volunteers were enrolled in this study.The respiratory tract microorganisms were detected by 16 S r RNA high-throughput sequencing technology.Through aspects such as alpha,beta and variance analysis,this study is designed to reveal the healthy people and patients with COPD airway micro ecological characteristics and the similarities and differences,to analyze relationship between changes in flora and disease,and to recognize the changes of microbial composition and abundance in stable COPD and acute exacerbation.The related clinical indicators and the influential factors of AECOPD patients with respiratory tract microbial flora were analyzed using a questionnaire which records attendance of human general information.Results 1.The microecological community structure of respiratory tract in COPD stable and acute exacerbations was different from that of healthy people.The alpha diversity of respiratory microecology was lowest in the acute exacerbation group and highest in the healthy group among the three study groups.Significant differences in beta diversity were observed in people with different periods of COPD compared to healthy people(P<0.05).However,the difference between the cohorts of patients with stable COPD and acute exacerbations was not significant(P>0.05).There was no obvious independent clustering between the two groups.The bacterial community composition of the acute exacerbation group showed an increase in common pathogenic bacteria.2.Compared with the healthy population,the relative abundance of the genus Pseudomonas was found to be increased significantly in the stable and acute exacerbation groups of COPD,while the relative abundance of Bacteroides was shown to be reduced to a significant extent,especially for the Prevotella among them.In addition,the relative abundance of the genus Pseudomonas was observed to be much higher in the acute exacerbation of COPD compared to the stable group,while the relative abundance of the phylum Bacteroides and Prevotella was detected to be lower(P<0.05).3.Long-term inhalation of combined corticosteroids/long-acting β2 agonists affects the community structure of respiratory microecology in patients with AECOPD,reduces alpha diversity(P<0.05).Smoking,gender and age did not cause changes in microecological diversity and community structure.Other clinical indicators(white blood cell count,red blood cell count,platelet count,neutrophil count,lymphocyte count,C-reactive protein,duration of disease,number of hospitalization per year,length of hospital stay,and body temperature)were not significantly correlated with respiratory microecological alpha diversity(P>0.05).Conclusion There are differences in the composition,abundance and diversity of respiratory microecology at different stages of COPD,which are different from those of healthy volunteers.The microecological diversity is the lowest in the population with acute exacerbations and the highest in the healthy.The occurrence and development of COPD may be related to the increase of the relative abundance of some pathogenic bacteria in the respiratory tract.The airway microecology of AECOPD patients is affected by corticosteroids/long-acting β2 agonists,while smoking,age and gender have no significant effect.Other clinical indicators,including blood routine,C-reactive protein and the number of hospitalizations per year,were not significantly correlated with respiratory microecological alpha diversity.This study provided new microecological data for the study of respiratory microecological diversity in China.