title: Correlation between the human fecal microbiota and depression.
abstract: BACKGROUND
  Depression is a chronic syndrome with a pathogenesis linked to various genetic, biological, and environmental factors. Several links between gut microbiota and depression have been established in animal models. In humans, however, few correlations have yet been demonstrated. The aim of our work was therefore to identify potential correlations between human fecal microbiota (as a proxy for gut microbiota) and depression.
  
  
  METHODS
  We analyzed fecal samples from 55 people, 37 patients, and 18 non-depressed controls. Our analyses were based on data generated by Illumina deep sequencing of 16S rRNA gene amplicons.
  
  
  RESULTS
  We found several correlations between depression and fecal microbiota. The correlations, however, showed opposite directions even for closely related Operational Taxonomic Units (OTU's), but were still associated with certain higher order phylogroups. The order Bacteroidales showed an overrepresentation (p = 0.05), while the family Lachnospiraceae showed an underrepresentation (p = 0.02) of OTU's associated with depression. At low taxonomic levels, there was one clade consisting of five OTU's within the genus Oscillibacter, and one clade within Alistipes (consisting of four OTU's) that showed a significant association with depression (p = 0.03 and 0.01, respectively).
  
  
  CONCLUSIONS
  The Oscillibacter type strain has valeric acid as its main metabolic end product, a homolog of neurotransmitter GABA, while Alistipes has previously been shown to be associated with induced stress in mice. In conclusion, the taxonomic correlations detected here may therefore correspond to mechanistic models.
authors.affiliation: Faculty of Education and Science, Hedmark University College, Hamar, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Naseribafrouei
authors.forename: K
authors.initials: K
authors.lastname: Hestad
authors.forename: E
authors.initials: E
authors.lastname: Avershina
authors.forename: M
authors.initials: M
authors.lastname: Sekelja
authors.forename: A
authors.initials: A
authors.lastname: Linløkken
authors.forename: R
authors.initials: R
authors.lastname: Wilson
authors.forename: K
authors.initials: K
authors.lastname: Rudi
mesh_terms: D000328:Adult; D003866:Depressive Disorder / Q000382:microbiology*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: 16SrRNA gene; Illumina deep sequencing; depression; gut microbiota