Analysis Of Microecological Characteristics Of Respiratory Tract Bacteria And Related Influencing Factors In Patients With Bronchial Asthma

Objective The thesis is to study the basic characteristics,similarities and differences of respiratory bacterial microecology between healthy people and patients with bronchial asthma,and to analyze the factors related to the diversity of airway microecology of asthma,which can provide new data for microecological studies of asthma patients and new ideas for individualized asthma treatment.Methods Sputum samples of patients with bronchial asthma and healthy people were collected.16 Sr DNA high-throughput sequencing technology was used to analyze the microecological characteristics of bacteria in the samples.The microecological characteristics of respiratory tract of patients with bronchial asthma and healthy people were analyzed from the differences of alpha diversity,beta diversity and genus level of bacteria respectively.The clinical information and demographic characteristics of the subjects were obtained by questionnaire survey,and the pulmonary function test results of patients with bronchial asthma were recorded,and correlation analysis of influencing factors was conducted.Results 1.The respiratory microecological structure of asthma patients differed from that of the healthy population,and the respiratory microecological structure of asthma patients in the well-controlled and incompletely controlled groups had their own characteristics and were significantly different.Besides,the well-controlled group and the incompletely controlled group had their own characteristics and significant differences in the respiratory microecological structure(P < 0.05).Beta diversity analysis: based on principal coordinate analysis(PCo A)weighted Uni Frac distance,PC1 contributed 42.12% and PC2 contributed 14.33%.There were significant differences in beta diversity among the three groups(P < 0.05).2.FEV1% 、FEV1/FVC% and ACT scores in asthmatics were positively correlated with alpha diversity,whereas glucocorticoid treatment was negatively correlated with alpha diversity in patients with asthma,which was statistically significant(P < 0.05).No correlation was observed for age,sex,body mass index(BMI),smoking,and long-term stay(rural/urban)(P > 0.05).Diversity analysis of asthma patients with allergic rhinitis and those without allergic rhinitis showed a difference in Shannon’s index between the two groups(P < 0.05).Lefse analysis was performed on the subgroups of bronchial asthma with and without allergic rhinitis,and differences were found at the level of individual genera(P< 0.05).The sputum of bronchial asthma patients with allergic rhinitis had higher abundance of Abiotrophia,Lautroptella,Capnocytophaga,Fusobacterium,Bergeyella,Actinobacillus,Granulicatella,and Neisseria.The sputum of bronchial asthmatic patients without allergic rhinitis had higher abundance of Selenomonas,Bordettella and Lauerella.Conclusion The respiratory microecological structure of asthma patients differed from that of the healthy population.The respiratory tract microecological diversity of asthma patients declined.The respiratory tract microecological diversity of asthma patients in incompletely controled group declined more than that in well-controled group.Changes in the composition of the airway flora in asthma patients may be related to poor disease control and comorbid allergic rhinitis.A correlation analysis found that the decrease in flora alpha diversity in asthmatic patients may be associated with a decrease in FEV1%,FEV1/FVC%,ACT score and the application of glucocorticoids.