| BackgroundSevere pneumonia is a common acute severe disease in clinic.Patients in the acute stage gradually enter the convalescence stage after adequate anti-infection and life-sustaining treatment.However,convalescent patients who experience long-term heavy use of anti-infective drugs/antibiotics usually develop severe intestinal flora imbalance,which leads to the translocation of intestinal bacteria and the introduction of metabolites into the blood circulation,causing systemic infection and reaggravation of the disease.Intestinal flora transplantation is a new treatment method to transplant the flora from the stool of a healthy person into the intestinal tract of a patient.Through intestinal flora transplantation,patients can quickly rebuild intestinal microecological structure,so as to alleviate intestinal diseases.The lung-intestinal axis regulates pulmonary inflammatory factors and phagocytic pathogens through intestinal flora and its metabolites,and plays an important role in mediating immune response and reshaping inflammation.Based on the theory of lung-intestinal axis,this study explores the therapeutic effect of intestinal flora transplantation on convalescent patients with severe pneumonia,and provides reference for comprehensive rehabilitation treatment of clinical patients with severe pneumonia.Objective1.To investigate the effects of intestinal flora transplantation on inflammation,immunity,blood lipid and intestinal flora in convalescence patients with severe pneumonia;2.To investigate the effect of intestinal flora transplantation on lower respiratory tract flora and its metabolites in convalescent patients with severe pneumonia.ParticipatesForty convalescent patients with severe pneumonia admitted to the First Affiliated Hospital of Guangzhou Medical University from December 1,2021 to December 31,2022 were included in the prospective non-randomized controlled study.They were divided into two groups according to the presence or absence of indications of intestinal flora transplantation and patients’ wishes.Twenty patients in recovery stage of severe pneumonia who underwent intestinal flora transplantation were defined as the flora transplantation group(FMT group),while 20 patients in recovery stage of severe pneumonia who were hospitalized at the same time without intestinal flora transplantation were defined as the normal saline transplantation group(NS group),and the FMT group underwent intestinal flora transplantation for 3consecutive days and was observed for 7 days after the transplantation.NS group was observed for 7 days after 3 consecutive days of normal saline transplantation.MethodClinical data and data of all patients were collected,stool and sputum were collected for 16 Sr DNA gene detection,and sputum was tested for non-target metabolomics.The therapeutic effects of intestinal flora transplantation on patients recovering from severe pneumonia were analyzed and demonstrated from the aspects of species composition,species diversity,differential species,gene function prediction and correlation analysis.Results1.After intervention,triglyceride(TG)and fecal Bristol score of FMT group were significantly decreased compared with that before intervention,while there was no significant difference in inflammation index.In NS group,after intervention,compared with before intervention,CRP,IL-6,IL-8 and other inflammatory indexes were significantly increased,while prealbumin(PAB)and CD4+/CD8+ were significantly decreased,while fecal Bristol score was not significantly different.2.Intestinal flora sequencing revealed:(1)The α diversity of intestinal microflora in the FMT group was significantly increased after intestinal flora transplantation,and β diversity analysis showed that the intestinal microecological structure in the FMT group was significantly different from that before transplantation.There were no significant differences in α diversity and βdiversity of intestinal microecology in NS group.(2)After intestinal flora transplantation in FMT group,the relative abundance of Fusobacteria was significantly increased and the relative abundance of Proteobacteria was significantly decreased(all P<0.05);Butyricimonas,Fusobacterium,Phascolarctobacterium and Streptococcus increased significantly while Enterococcus decreased significantly(all P<0.05).(3)The abundance of KEGG metabolic pathway predictive functional genes showed that the Phosphonate and phosphinate metabolism pathways of intestinal flora in the FMT group were significantly down-regulated,while mineral absorption pathways were significantly up-regulated.(4)Correlation analysis showed that triglyceride(TG)was positively correlated with Escherichia-Shigella(r=0.4,P<0.01)and was positively correlated with Parabacteroides(r=0.5,P<0.001);Low density lipoprotein cholesterol(LDL-C)is positively correlated with Butyricimonas(r=0.3,P< 0.05),was negatively correlated with Veillonella(r=-0.3,P<0.05);Procalcitonin(PCT)was positively correlated with Enterococcus(r=0.4,P<0.01)and had a negative correlation with Bacteroides(r=-0.4,P<0.05);Interleukin 6(IL-6)was positively correlated with Bacteroides(r=0.3,P<0.05);Interleukin 8(IL-8)was positively correlated with Bacteroides(r=0.3,P<0.05).3.Sequencing findings of airway microflora:(1)Intestinal flora transplantation had no significant effect on lower airway flora diversity in patients recovering from severe pneumonia;However,there were significant differences in the lower airway microflora structure of patients in FMT group before and after intervention,while no significant differences in the lower airway microflora structure of patients in NS group before and after intervention.(2)After intestinal flora transplantation in FMT group,the relative abundance of cyanobacteria decreased significantly,and the relative abundance of Aggregatibacter in airway dominant bacteria increased significantly.The relative abundance of Bacteroides,Faecalibacterium,Blautia,Parabacteroides and Bifidobacterium increased significantly(P<0.05);The relative abundance of Brucella and Pedomicrobium decreased significantly(both P<0.05).(3)There was no significant difference in the abundance of functional genes predicted by lower airway microflora in FMT group before and after intervention.(4)Correlation analysis between airway dominant bacteria and clinical indicators showed that interleukin-6(IL-6)was positively correlated with Klebsiella(r=0.9,P<0.001);Interleukin-8(IL-8)was positively correlated with Klebsiella(r=0.6,P<0.001);Correlation analysis between intestinal flora and airway flora showed that airway Pseudomonas was positively correlated with intestinal butyricimonas(r=0.5,P<0.01);Airway Pseudomonas was positively correlated with intestinal Fusobacterium(r=0.6,P<0.001);Airway Acinetobacter was positively correlated with Enterococcus(r=0.3,P<0.05);Airway Serratia was positively correlated with intestinal Hungatella(r=0.5,P<0.001);Airway Streptococcus was positively correlated with intestinal Prevotella＿9(r=0.4,P<0.01);Airway Haemophilus was positively correlated with intestinal Hungatella(r=0.3,P<0.05);Airway Neisseria was positively correlated with intestinal Morganella(r=0.4,P<0.05).4.Non-targeted metabolomics detection results of sputum(1)Differential metabolite analysis showed that Bis(2-methylpropanoyloxy)-9,10-epoxy-p-Mentha-1,3,5-triene,Exalamide and Testosterone were significantly upregulated in the FMT group Metabolites such as glucuronide,His-Val-Thr-Glu-Glu and Pro-Met-Asn.Significantly up-regulated metabolites in NS group were Pro-CysLeu,1-Eicosenoyl-glycerol and Leu-His-Gly-Phe-His,etc.The significantly downregulated metabolites were Furaneol 4-glucoside and Taurohyodeoxycholic acid.(2)KEGG metabolic pathway annotation and enrichment analysis revealed that the differential metabolites of FMT patients were mainly related to the following pathways: aldosterone synthesis and secretion,neuroactive ligand-receptor interaction,steroid hormone biosynthesis,prolactin signaling pathway,Parkinson’s disease and other metabolic pathways and diseases;The content of adenosine diphosphate(ADP)in oxidative phosphorylation pathway was significantly up-regulated.(3)Correlation analysis of lower airway differential metabolites and differential intestinal flora in FMT group showed that intestinal Lactobacillus was significantly positively correlated with testosterone glucosidic acid in sputum metabolites.Conclusions(1)Intestinal flora transplantation can lower triglyceride level,maintain inflammation and immune homeostasis,and improve fecal characteristics of patients in the convalescence stage of severe pneumonia;(2)Intestinal flora transplantation can improve the diversity and structure of intestinal flora in convalescence patients with severe pneumonia;(3)There was no significant effect of intestinal flora transplantation on lower respiratory tract flora diversity in patients recovering from severe pneumonia,but it could change the structure of lower respiratory tract flora.(4)Intestinal flora transplantation can significantly up-regulate the enrichment factor of steroid hormone biosynthesis pathway in the lungs of patients recovering from severe pneumonia. |
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