title: Obesity in school-aged children and its correlation with gut E.coli and Bifidobacteria: a case-control study.
abstract: BACKGROUND
  To determine the correlation between obesity in school-aged children and imbalance of gut microbes by examining the ratio change of intestinal Bifidobacteria and E.coli in obese children compared to non-obese controls.
  
  
  METHODS
  A hospital-based 1:1 case-control study was performed. Fecal samples of the subjects were collected for DNA extraction and analyzed by quantitative real-time PCR (qPCR) to determine the copy number of Bifidobacteria and E.coli. The ratio of two microbes (B/E) was then calculated and statistically analyzed.
  
  
  RESULTS
  Subjects of the obesity group and control group showed no significant difference in age, gender or height (P > 0.05); whereas they had significant differences in body weight and BMI. Copy numbers of Bifidobacteria and E.coli per gram of wet fecal samples were first determined using qPCR in both obese and normal groups, which were further used for the calculation of B/E ratio. We found that B/E ration in the two groups showed significant difference (P < 0.05). Corrected χ(2) test was performed for the two groups against B/E < 1, and it was found that there was a positive correlation (OR = 719.2, OR 95% C.I. = 81.57-6341.18) between B/E ratio decrease with childhood obesity.
  
  
  CONCLUSIONS
  The obese children have a lower amount of Bifidobacteria and higher amount of E.coli (smaller B/E ratio) compared to normal non-obese children. It was suggested that obesity in children may be associated with the imbalance of gut microbes.
authors.affiliation: Department of Pediatrics, West China University Second Hospital, Sichuan University, 610041, Chengdu, Sichuan, China. 23132875@qq.com.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Gao
authors.affiliation: Open Laboratory, West China Institute for Women's and Children's Health, 610041, Chengdu, Sichuan, China. 1002113878@qq.com.
authors.forename: Ruizhen
authors.initials: R
authors.lastname: Jia
authors.affiliation: Pulmonary Vascular Remodeling Research Unit Laboratory, West China Institute for Women's and Children's Health, 610041, Chengdu, Sichuan, China. 1154792673@qq.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Xie
authors.affiliation: Department of Laboratory Medicine, Sichuan University West China Second Hospital, 610041, Chengdu, Sichuan, China. hanhan840106@163.com.
authors.forename: Linghan
authors.initials: L
authors.lastname: Kuang
authors.affiliation: Department of Pediatrics, West China University Second Hospital, Sichuan University, 610041, Chengdu, Sichuan, China. 348030966@qq.com.
authors.forename: Ling
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Pediatrics, West China University Second Hospital, Sichuan University, 610041, Chengdu, Sichuan, China. wcm0220@sina.com.
authors.forename: Chaomin
authors.initials: C
authors.lastname: Wan
mesh_terms: D001644:Bifidobacterium / Q000235:genetics / Q000302:isolation & purification*; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D004926:Escherichia coli / Q000235:genetics / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D008297:Male; D063766:Pediatric Obesity / Q000382:microbiology*; D060888:Real-Time Polymerase Chain Reaction