A Clinical Study On The Changes Of Lung Microecology And Intestinal Microecology In ARDS Patients

Objective:To investigate the composition and changes of intestinal and pulmonary flora in ARDS patients.Methods:This was a prospective observational clinical study.Patients with ARDS undergoing mechanical ventilation and non-ARDS undergoing mechanical ventilation were enrolled as the experiment group and control group separately.Get all the patients’blood,stool samples and alveolar lavage by fiberoptic bronchoscopy lavage specimen of technology acquisition.The composition of flora in stool and alveolar lavage were detected by 16s-rRNA gene sequencing technology,and the results were taken into biological information analysis,including OUT classification test、alpha diversity、beta diversity and multiple variable analysis,etc.,so as to show the composition and changes of intestinal and pulmonary flora in ARDS patients.Results:A total of 21 ARDS patients with mechanical ventilation and 22 non-ARDS patients with mechanical ventilation were enrolled during the period from March 2019 to October 2019.The intestinal contents of flora of ARDS patients were dominated by Bacteroidetes,Proteobacteria,Firmicutes,Actinobacteria and Nitrospirae,with the relative abundance of 38.49%、32.73%、21.30%、2.48%、1.44%,respectively.Compared with the control group,the Chaol index of intestinal flora of ARDS patients was significantly increased(P<0.05),while there was no difference between Shannon index and Simpson index(P>0.05).The beta diversity analysis showed that there were significant differences in microflora between different groups(Adonis<0.05).The differential intestinal flora of ARDS patients included Fusobacteria,Bacteroidetes and Proteobacteria.The lung’s flora of ARDS patients were dominated by Bacteroidetes,Firmicutes,Proteobacteria,Ep sil onb acteraeota,Actinobacteria,the relative abundance were 30.74%、28.61%、24.83%、6.72%、3.05%,respectively;Compared with the control group,the Chao1 index in ARDS patients was significantly reduced(P<0.05),and there was no difference between Shannon index and Simpson index(P>0.05).The comparison of beta diversity showed that there were significant differences in microflora between different groups(Adonis<0.05).The differential lung’s flora of ARDS patients included Deferribacteres,Epsilonbacteraeota,Patescibacteria,Margulisbacteria,etc.The lung flora and intestinal flora of ARDS patients on days 1,2,3,5 and 7 were the same as the top five in terms of relative abundance at the phylum level,all of which were Bacteroidetes,Proteobacteria,Firmicutes,Actinobacteria and Nitrospirae.Conclusion:Compared with mechanically ventilated non-ARDS patients,the richness and diversity of intestinal flora of ARDS patients were both increased,and the pulmonary flora richness of ARDS patients decreased,while the diversity did not change significantly.Compared with mechanically ventilated non-ARDS patients,the intestinal flora of ARDS patients was significantly different with increased richness and no significant change in diversity,while the pulmonary flora richness of ARDS patients was decreased,while no significant change in diversity.The pulmonary flora and intestinal flora of ARDS patients were similar,with bacteroidetes,proteobacteria and firmicutes dominating.