title: Differences in gut microbiota composition between obese and lean children: a cross-sectional study.
abstract: BACKGROUND
  An altered gut microbiota composition has recently been linked to obesity. The principal aim of this study is to investigate and compare the gut microbiota composition in obese and lean children. Secondly, associations between analysed gut bacterial species, dietary compounds, energy intake and biochemical blood parameters are evaluated.
  
  
  METHODS
  In this prospective cross-sectional study, 26 overweight/obese (mean BMI: 28.7 ± 6.5) and 27 lean (mean BMI: 16.5 ± 2.1) children aged 6 to 16 were included. Faecal samples were collected and subjected to selective plating and quantitative real-time PCR (qPCR) in order to determine the concentrations of bacterial species belonging to the genera: Bacteroides, Bifidobacterium, Clostridium, Staphylococcus and Lactobacillus. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was applied for an in-depth identification of species of Bacteroides fragilis group. Differences in the concentrations of gut bacterial species between obese and lean children were statistically analysed using Mann Whitney U test. Subsequently, random forest analysis and multiple linear regression analysis were performed in order to test associations between gut bacterial species, dietary compounds and blood parameters.
  
  
  RESULTS
  Obese children showed an elevated Firmicutes-to-Bacteroidetes ratio compared with lean children. Furthermore, low relative proportions of B. vulgatus and high concentrations of Lactobacillus spp. were observed in the obese microbiota. In all children, Staphylococcus spp. were positively associated with energy intake. Additionally, in obese children, Lactobacillus spp. were positively associated with plasma hs-CRP.
  
  
  CONCLUSIONS
  Our findings corroborate a significant difference in the gut microbiota composition of important bacterial species between obese and lean children. In future, non-invasive manipulation of gut microbiota composition in early infancy could offer a new approach to manage childhood obesity and associated disorders.
authors: Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Antwerp, Belgium. liene.bervoets@uhasselt.be.
authors: Liene
authors: L
authors: Bervoets
authors: Kim
authors: K
authors: Van Hoorenbeeck
authors: Ineke
authors: I
authors: Kortleven
authors: Caroline
authors: C
authors: Van Noten
authors: Niel
authors: N
authors: Hens
authors: Carl
authors: C
authors: Vael
authors: Herman
authors: H
authors: Goossens
authors: Kristine N
authors: KN
authors: Desager
authors: Vanessa
authors: V
authors: Vankerckhoven
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