title: Quantitative profiling of gut microbiota of children with diarrhea-predominant irritable bowel syndrome.
abstract: OBJECTIVE
  Human intestinal microbiota has a number of important roles in human health and is also implicated in several gastrointestinal disorders. The goal of this study was to determine the gut microbiota in two groups of pre- and adolescent children: healthy volunteers and children diagnosed with diarrhea predominant irritable bowel syndrome (IBS-D).
  
  
  METHODS
  Phylogenetic Microbiota Array was used to obtain quantitative measurements of bacterial presence and abundance in subjects ’ fecal samples. We utilized high-throughput DNA sequencing, quantitative PCR, and fluorescent in situ hybridization to confirm microarray findings.
  
  
  RESULTS
  Both sample groups were dominated by the phyla Firmicutes, Bacteroidetes, and Actinobacteria, which cumulatively constituted 91 % of overall sample composition on average. A core microbiome shared among analyzed samples encompassed 55 bacterial phylotypes dominated by genus Ruminococcus ; members of genera Clostridium , Faecalibacterium, Roseburia, Streptococcus , and Bacteroides were also present. Several genera were found to be differentially abundant in the gut of healthy and IBS groups: levels of Veillonella , Prevotella , Lactobacillus , and Parasporo bacterium were increased in children diagnosed with IBS, whereas members of Bifidobacterium and Verrucomicrobium were less abundant in those individuals. By calculating a nonparametric correlation matrix among abundances of different genera in all samples, we also examined potential associations among intestinal microbes. Strong positive correlations were found between abundances of Veillonella and both Haemophilus and Streptococcus , between Anaerovorax and Verrucomicrobium , and between Tannerella and Anaerophaga .
  
  
  CONCLUSIONS
  Although at the higher taxonomical level gut microbiota was similar between healthy and IBS-D children, specific differences in the abundances of several bacterial genera were revealed. Core microbiome in children was dominated by Clostridia. Putative relationships identified among microbial genera provide testable hypotheses of cross-species associations among members of human gut microbiota
authors.affiliation: Department of Biochemistry and Molecular Biology, Wright State University, Dayton, Ohio, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Rigsbee
authors.forename: Richard
authors.initials: R
authors.lastname: Agans
authors.forename: Vijay
authors.initials: V
authors.lastname: Shankar
authors.forename: Harshavardhan
authors.initials: H
authors.lastname: Kenche
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Khamis
authors.forename: Sonia
authors.initials: S
authors.lastname: Michail
authors.forename: Oleg
authors.initials: O
authors.lastname: Paliy
mesh_terms: D000293:Adolescent; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics; D003967:Diarrhea / Q000382:microbiology*; D005260:Female; D016680:Genome, Bacterial; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D043183:Irritable Bowel Syndrome / Q000382:microbiology*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D060888:Real-Time Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D004269:DNA, Bacterial