| Objective To investigate the changes of intestinal microecology and the correlation between gut and lung microflora in patients with ventilator-associated-pneumonia(VAP).Methods A prospective observational study was conducted.Thirty-one patients with VAP admitted to the department of critical care medicine of General Hospital of Ningxia Medical University from May 1st 2019 to May 1st 2020 were enrolled.Feces and Bronchoalveolar Fluid(BALF)samples from thirty-one patients with VAP and faces samples form twenty healthy volunteers were gathered and store in a refrigerator at-80℃.Finally,using 16Sr RNA sequencing technology to analizy flora structure and composition of biological information,and comprehensive sequencing results and clinical data of patients with unified analysis.Results1.Characteristics of intestinal flora in patients with VAP(1).Theαdiversity of microecology was analyzed by Ace index,Chao index,Shannon index and Simpson index.Theαdiversity of fecal flora in VAP group was lower than that in healthy control group,and the difference was statistically significant(P<0.05).(2).The principal coordinate analysis(PCo A)showed that the intestinal community structure of VAP group was significantly different from that of healthy control group.Adonis multivariate analysis of variance showed that there was significant difference in the flora structure between VAP group and healthy control group(R~2=0.17,P<0.01).(3).Compared with the healthy control group,the composition of intestinal flora in VAP group showed a decreasing trend of Bacteroidetes and Firmicutes,while an increasing trend of Proteobacteria,with no statistical significance(P>0.05).At the genus level,beneficial bacteria such as Prevotella,Coprobacillus,Pseudobutyrivibrio,Ruminococcus,Rossiella,Helicobacter and Bifidobacterium showed a decreasing trend,and the difference was statistically significant(P<0.05).The opportunistic pathogenic bacteria Escherichia coli and pathogenic enterococcus showed an increasing trend,and the composition of pathogenic enterococcus had statistical significance(P<0.05).The proportion of Acinetobacter was significantly increased,and the difference was statistically significant(P<0.05).2.Characteristics of pulmonary flora in patients with VAPThe abundance of bacteria in the BALF of VAP patients was as follows:Streptococcus(0.12%),Prevotella(0.07%),Sphingomonas(0.07%),Acinetobacter(0.07%),Escherichia coli(0.07%),Staphylococcus(0.06%),Bacteroidetes(0.06%),their was some enteric bacteria and has high abundance.3.Gut-lung association in patients with VAP(1).The diversity of flora in BALF of VAP patients were higher than those offecal flora.Among them,Ace index,Chao index and Shannon index showed statistically significant differences(P>0.05),but there was no significant difference in Simpson index(P>0.05).(2).In the sequencing results of feces and BALF of VAP patients,there were some intestinal related bacteria groups with high abundance,such as Escherichia Shigella,Faecalibacterium,Bacteroides and Lachnospira,etc,Those intestinal associated flora were dominant in the lungs of some patients.(3).In 31 VAP patients,clinical culture of suspicious bacteria in BALF was found in20 cases,and the same suspected pathogens also existed in the 17 patients.(4).Compared with the VAP group,the Jaccard similarity index of the VAP combined with sepsis group was increased,and the difference was statistically significant(P<0.01).(5).Compared with other surgical groups,the Jacard similarity index of VAP patients in the abdominal surgery group was higher,and the difference was statistically significant(P<0.01).Conclusion1.The intestinal flora in VAP patients is disturbed,which is manifested as the decrease of the abundance and diversity of intestinal flora,the decrease of beneficial bacteria,and the expansion of pathogenic bacteria or opportunistic pathogens.2.There may be a certain gut-lung association in VAP patients. |
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