title: Relative Abundance in Bacterial and Fungal Gut Microbes in Obese Children: A Case Control Study.
abstract: Differences in relative proportions of gut microbial communities in adults have been correlated with intestinal diseases and obesity. In this study we evaluated the gut microbiota biodiversity, both bacterial and fungal, in obese and normal-weight school-aged children.
  
  
  
  We studied 28 obese (mean age 10.03 ± 0.68) and 33 age- and sex-matched normal-weight children. BMI z-scores were calculated, and the obesity condition was defined according to the WHO criteria. Fecal samples were analyzed by 16S rRNA amplification followed by denaturing gradient gel electrophoresis (DGGE) analysis and sequencing. Real-time polymerase chain reaction (PCR) was performed to quantify the most representative microbial species and genera.
  
  
  
  DGGE profiles showed high bacterial biodiversity without significant correlations with BMI z-score groups. Compared to bacterial profiles, we observed lower richness in yeast species. Sequence of the most representative bands gave back Eubacterium rectale, Saccharomyces cerevisiae, Candida albicans, and C. glabrata as present in all samples. Debaryomyces hansenii was present only in two obese children. Obese children revealed a significantly lower abundance in Akkermansia muciniphyla, Faecalibacterium prausnitzii, Bacteroides/Prevotella group, Candida spp., and Saccharomyces spp. (P = 0.031, P = 0.044, P = 0.003, P = 0.047, and P = 0.034, respectively).
  
  
  
  Taking into account the complexity of obesity, our data suggest that differences in relative abundance of some core microbial species, preexisting or diet driven, could actively be part of its etiology. This study improved our knowledge about the fungal population in the pediatric school-age population and highlighted the need to consider the influence of cross-kingdom relationships.
authors.affiliation: 1 Department of Health Sciences, Università degli Studi di Milano , Milan, Italy .
authors.forename: Francesca
authors.initials: F
authors.lastname: Borgo
authors.affiliation: 2 Department of Pediatrics, San Paolo Hospital , Milan, Italy .
authors.forename: Elvira
authors.initials: E
authors.lastname: Verduci
authors.affiliation: 1 Department of Health Sciences, Università degli Studi di Milano , Milan, Italy .
authors.forename: Alessandra
authors.initials: A
authors.lastname: Riva
authors.affiliation: 1 Department of Health Sciences, Università degli Studi di Milano , Milan, Italy .
authors.forename: Carlotta
authors.initials: C
authors.lastname: Lassandro
authors.affiliation: 2 Department of Pediatrics, San Paolo Hospital , Milan, Italy .
authors.forename: Enrica
authors.initials: E
authors.lastname: Riva
authors.affiliation: 1 Department of Health Sciences, Università degli Studi di Milano , Milan, Italy .
authors.forename: Giulia
authors.initials: G
authors.lastname: Morace
authors.affiliation: 1 Department of Health Sciences, Università degli Studi di Milano , Milan, Italy .
authors.forename: Elisa
authors.initials: E
authors.lastname: Borghi
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D005243:Feces / Q000382:microbiology; D005247:Feeding Behavior; D005658:Fungi / Q000145:classification / Q000302:isolation & purification*; D000069196:Gastrointestinal Microbiome / Q000502:physiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D063766:Pediatric Obesity / Q000209:etiology / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D012336:RNA, Ribosomal, 16S