title: The placental membrane microbiome is altered among subjects with spontaneous preterm birth with and without chorioamnionitis.
abstract: Preterm birth (PTB) is a leading cause of neonatal morbidity and mortality and is not uncommonly associated with chorioamnionitis. We recently have demonstrated that the placenta harbors a unique microbiome with similar flora to the oral community. We also have shown an association of these placental microbiota with PTB, history of antenatal infection, and excess maternal weight gain. On the basis of these previous observations, we hypothesized that the placental membranes would retain a microbiome community that would vary in association with preterm birth and chorioamnionitis.
  
  
  
  In the current study, we aimed to examine the differences in the placental membrane microbiome in association with PTB in both the presence and absence of chorioamnionitis and/or funisitis using state-of-the-science whole-genome shotgun metagenomics.
  
  
  
  This was a cross-sectional analysis with 6 nested spontaneous birth cohorts (n = 9-15 subjects/cohort): Term gestations without chorioamnionitis, term with chorioamnionitis, preterm without chorioamnionitis, preterm with mild chorioamnionitis, preterm with severe chorioamnionitis, and preterm with chorioamnionitis and funisitis. Histologic analysis was performed with Redline's criteria, and inflammatory cytokines were analyzed in the cord blood. DNA from placental membranes was extracted from sterile swabs collected at delivery, and whole-genome shotgun sequencing was performed on the Illumina HiSeq platform. Filtered microbial DNA sequences were annotated and analyzed with MG-RAST (ie, Metagenomic Rapid Annotations using Subsystems Technology) and R.
  
  
  
  Subjects were assigned to cohorts on the basis of gestational age at delivery and independent scoring of histologic chorioamnionitis. We found that preterm subjects with severe chorioamnionitis and funisitis had increases in cord blood inflammatory cytokines. Of interest, although the placental membrane microbiome was altered in association with severity of histologic chorioamnionitis (permutational multivariate analysis of variance P = .005), there was no observable impact with either betamethasone or antibiotic treatment. In preterm subjects with chorioamnionitis, we found a high abundance of both urogenital and oral commensal bacteria. These alterations in the microbiome were accompanied by significant variation (P < .05) in microbial metabolic pathways important in the glucose-fed pentose phosphate pathway (term subjects), or glycerophopholipid metabolism, and the biosynthesis of the siderophore group nonribosomal peptides (preterm subjects).
  
  
  
  Consistent with ours and others previous findings, women who experienced spontaneous PTB harbor placental microbiota that further differed by severity of chorioamnionitis. Integrative metagenomic analysis revealed significant variation in distinct bacterial metabolic pathways, which we speculate may contribute to risk of preterm birth with and without severe chorioamnionitis.
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Amanda L
authors.initials: AL
authors.lastname: Prince
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Jun
authors.initials: J
authors.lastname: Ma
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Paranthaman S
authors.initials: PS
authors.lastname: Kannan
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Manuel
authors.initials: M
authors.lastname: Alvarez
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Tate
authors.initials: T
authors.lastname: Gisslen
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: R Alan
authors.initials: RA
authors.lastname: Harris
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Emma L
authors.initials: EL
authors.lastname: Sweeney
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Christine L
authors.initials: CL
authors.lastname: Knox
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Donna S
authors.initials: DS
authors.lastname: Lambers
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Alan H
authors.initials: AH
authors.lastname: Jobe
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Claire A
authors.initials: CA
authors.lastname: Chougnet
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Suhas G
authors.initials: SG
authors.lastname: Kallapur
authors.affiliation: Departments of Obstetrics & Gynecology, Division of Maternal-Fetal Medicine (Drs Prince, Ma, Harris, and Aagaard), Molecular & Human Genetics (Drs Harris and Aagaard), Molecular & Cell Biology (Dr Aagaard), and Molecular & Cellular Physiology (Dr Aagaard), Baylor College of Medicine, Houston, TX; Divisions of Neonatology (Drs Kannan, Gisslen, Jobe, and Kallapur and Mr Alvarez) and Immunology (Dr Chougnet), the Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH; Queensland University of Technology, Brisbane, QLD, Australia (Drs Sweeney and Knox); and Department of Obstetrics, Maternal-Fetal Medicine, Good Samaritan Hospital, Cincinnati, OH (Dr Lambers).
authors.forename: Kjersti M
authors.initials: KM
authors.lastname: Aagaard
mesh_terms: D002087:Butyrates / Q000378:metabolism; D002821:Chorioamnionitis / Q000382:microbiology*; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D020404:Glycerophospholipids / Q000378:metabolism; D006801:Humans; D056186:Metagenomics; D064307:Microbiota; D010427:Pentose Phosphate Pathway; D010920:Placenta / Q000382:microbiology*; D011247:Pregnancy; D047928:Premature Birth; D012256:Riboflavin / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012720:Severity of Illness Index; D047929:Term Birth
chemical_list: D002087:Butyrates; D004269:DNA, Bacterial; D020404:Glycerophospholipids; D012256:Riboflavin
keywords: chorioamnionitis; funisitis; microbiome; preterm birth; whole-genome shotgun metagenomics