title: Metagenomic Analysis Reveals Dynamic Changes of Whole Gut Microbiota in the Acute Phase of Intensive Care Unit Patients.
abstract: Metagenomic analysis targeting the 16S rRNA gene has made it possible to characterize the vast array of microorganisms contained in the gut.
  
  
  
  The purpose of this study was to evaluate how gut microbiota change in intensive care unit (ICU) patients in the acute phase after admission.
  
  
  
  This prospective observational cohort study investigated 12 patients admitted to a single ICU of a large urban tertiary referral hospital. All patients were mechanically ventilated on admission. Fecal samples were collected from patients on days 1-2, 2-4, 5-8, and 7-10 after admission. DNA was extracted from fecal samples, and 16S rRNA deep sequencing was performed to monitor gut changes.
  
  
  
  Bacteria belonging to the phyla Firmicutes or Bacteroidetes were predominant in each sample. We observed serial dynamic changes in the percentages of Bacteroidetes and Firmicutes that were significantly altered during study period (p < 0.05). A ratio of Bacteroidetes to Firmicutes (B/F ratio) of >10 was seen in four of the six patients who died, whereas a B/F ratio of <0.10 was seen in only one of the six deaths. None of the survivors had a B/F ratio of >10 or <0.10. There was a statistical difference in the B/F ratio between the dead patients and survivors (p = 0.022).
  
  
  
  Dynamic changes in gut microbiota at the phylum level of ICU patients during the acute phase were identified by high-throughput DNA sequencing. An extreme imbalance in gut microbiota may be associated with prognosis in critically ill patients.
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan. ojimarionet999@hp-emerg.med.osaka-u.ac.jp.
authors.forename: Masahiro
authors.identifier: 0000-0001-7490-1539
authors.initials: M
authors.lastname: Ojima
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Motooka
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Shimizu
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Gotoh
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
authors.forename: Ayumi
authors.initials: A
authors.lastname: Shintani
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Yoshiya
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ogura
authors.affiliation: Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Iida
authors.affiliation: Department of Traumatology and Acute Critical Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, 565-0871, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimazu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D007362:Intensive Care Units; D056186:Metagenomics; D064307:Microbiota / Q000235:genetics*; D008875:Middle Aged; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Bacteroidetes; DNA sequencing; Intensive care; Metagenome; Metagenomics; Microbiota; RNA, Ribosomal, 16S; Sepsis