Study On Microecological Status Of Respiratory Tract Flora And Intestinal Flora In Patients With Acute Exacerbation Of Chronic Obstructive Pulmonary Disease

Objective: To observe the distribution of respiratory tract and intestinal flora in patients with AECOPD,and to compare the types and proportions of respiratory tract and intestinal flora between normal people and AECOPD patients,we can obtain the changes of flora in patients with AECOPD and explore the relationship between microecological changes and disease,then we can find new ideas to the prevention and control of AECOPD.Methods: 11 patients with AECOPD were enrolled by medical history,physical examination and pulmonary function examination,and 9 healthy controls matched with age and smoking history were selected.The respiratory tract and intestinal tract samples were collected to extract bacterial DNA;we used 16 s RNA sequencing technology data for collection and statistical analysis,to observe the distribution of flora in patients with AECOPD,and to explore the relationship between the changes of bacterial flora and the disease.Results:1.Analysis of respiratory tract flora in AECOPD group and healthy control group:(1)Analysis of bacterial abundance index: the values of Chao1 and Ace in AECOPD group were lower than those in control group,with no statistical difference(P>0.05).Analysis of bacterial diversity index: Shannon value of AECOPD group was lower than that of control group,with statistical difference(P<0.05),Simpson value was higher than that of control group,with no statistical difference(P>0.05)(2)At the phylum level,the main phylum of respiratory tract in AECOPDgroup(B)and healthy control group(A)were Bacteroidetes,Firmicutes,Actinobacteria,Fusobacteria and Proteobacteria,accounting for 27.26%,24.33%,16.59%,12.52% and11.08% of all respiratory tract samples,respectively.The total relative abundance of these five phylum was more than 90%.Among the top five phylum,the relative abundance of Bacteroidetes(24.99% vs 30.05%)decreased,Actinobacteria(19.71% vs12.77%)and Proteobacteria(12.97% vs 8.77%)increased in AECOPD group(B)compared with healthy control group(A).There was no significant difference in Firmicutes(24.39% vs 24.25%)and Fusobacteria(12.59% vs 12.43%).(3)At the genus level,Prevotella,Rothia,Fusobacterium,Prevotella＿7,Streptococcus,Porphyromonas,Leptotrichia,Neisseria and Veillonella were the most abundant genera in group A and B.Group B showed an increase in the number of Rothia(13.65% vs8.86%),Streptococcus(9.82% vs 6.23%)and Neisseria(7.01% vs 3.68%)compared with group A,the content of other major bacteria was similar between the two groups.2.Gut microbiota analysis between AECOPD and healthy control group:(1)Analysis of bacterial abundance index: the values of Chao1 and Ace in AECOPD group were lower than those in control group,with no statistical difference(P>0.05).The Shannon value of AECOPD group was lower than that of control group,Simpson value was higher than that of control group,there were no statistical difference(P>0.05).(2)At the phylum level,Firmicutes,Bacteroidetes and Proteobacteria were the main phylum in the intestinal tract of AECOPD group(D)and healthy control group(C),accounting for 56.17%,38.98% and 3.49% of all intestinal samples,respectively.The total relative abundance of these three phylum accounted for more than 95% of the total samples.Among the top three phylum,the relative abundance of Proteobacteria(5.36%vs 1.21%)increased and Firmicutes(53.00% vs 60.04%)decreased in AECOPD group(D)compared with healthy control group(C).However,the relative abundance of Bacteroidetes(39.50% vs 38.34%)showed no significant difference between the two groups.At the phylum level,the main flora of the two groups were similar,but the content of Fusobacteria in the lower phylum was significantly higher in AECOPD group than in the control group(0.72% vs 0.00%).(3)At the genus level,Faecalibacterium,Bacteroides,Prevotella＿9,Ruminococcaceae＿UCG＿002,[Eubacterium]＿rectale＿group were more abundant in both groups C and D.The top three genus in both groups were Faecalibacterium,Bacteroides,Prevotella＿9.Compared with group C,group D showed differences in the content of common major bacteria,showing the relative abundance of Faecalibacterium(23.59% vs 17.70%),Bacteroides(25.08% vs 10.33%)increased and the relative abundance of Prevotella＿9(10.79% vs 22.62%)、 Ruminococcaceae＿UCG＿002(1.65%vs 4.54%)and [Eubacterium]＿rectale＿group(2.56% vs 5.37%)decreased.Conclusions:1.The main types of respiratory flora in AECOPD patients and healthy people are Bacteroidetes,Firmicutes,Actinobacteria,Fusobacteria and Proteobacteria.2.The composition of respiratory tract flora in AECOPD patients was different from that in healthy people,which showed that the abundance of some pathogenic bacteria increased and the beneficial bacteria decreased.3.There are differences in the composition of respiratory tract flora between patients with AECOPD and healthy people.The diversity of respiratory tract flora in patients with AECOPD decreases,which may be the reason for the occurrence and development of the disease.4.The composition of intestinal flora in AECOPD patients is similar to that in healthy people.Firmicutes,Bacteroidetes and Proteobacteria are the main phylum in both phylum levels.5.The expression of individual phylum and genus in gut flora between the two groups are different.It is not ruled out that the changes are related to the occurrence of the disease,but it still needs further verification.6.The abundance and diversity of gut flora in AECOPD patients were less than healthy control group,but the difference was not significant.We should expand the sample size to verify the relationship between the diversity and abundance of intestinal flora and AECOPD.