Objective  To compare the quantity and distribution of intestinal Bacteroides thetaiotaomicron (Bt) and Bifidobacterium (Bf) among school-age children with different somatotypes and to explore the relationship between intestinal bacteria and body weight for providing evidences to develop appropriate intervention measures for regulating intestinal flora balance and promoting health in the children.

  Methods  We collected fecal samples from 166 children aged 6 – 11 years in a primary school in Nanjing city from November to December 2017. The quantity of intestinal Bt and Bf in the samples were detected with real time fluorogenetie quantitative PCR and the detection data were analyzed by body mass index (BMI)-defined somatotype among the children.

  Results  The median (quartile range QR) for quantity of intestinal Bt were 4.79 (QR: 4.69 – 5.36), 4.77 (QR: 4.69 – 5.44) and 5.00 (QR: 4.93 – 5.74) copies/μl for the pupils with obesity, overweight, and normal weight; the median (QR) of Bf in samples from obese, overweight, and normal weight pupils were 7.33 (QR: 7.16 – 7.57, 8.31 (QR: 8.11 – 8.47) and 8.31 (QR: 8.18 – 8.54), respectively. The distribution of intestinal Bt and Bf differed significantly by somatotype (all P < 0.05) but not by age and sex groups (both P > 0.05) among the pupils.

  Conclusion  The amount of Bacteroides thetaiotaomicron and Bifidobacterium in intestinal tract of school age children are related to somatotype, but not to age and sex among school-age children.