Distinct oral and fecal microbiota composition in preschool children with overweight/obesity: a cross-sectional study.

Children with overweight/obesity exhibited lower richness and diversity of fecal microbiota compared to normal-weight controls.

• Study included 47 preschool children aged 3 to 6 with obesity/overweight and 34 age-matched normal-weight controls.
• Samples collected included saliva, oral mucosal plaque, supragingival dental plaque, and fecal samples.
• Microbial analysis was performed using 16S rRNA gene sequencing.
• The reduction in richness and diversity was specific to fecal microbiota, not reported for oral niches.

Distinct niche-specific clustering was observed across different oral niches in preschool children.

• The three oral sample types examined were saliva, oral mucosal plaque, and supragingival dental plaque.
• Niche-specific clustering was observed across both the overweight/obesity group and the control group.
• This finding suggests that different oral microenvironments harbor compositionally distinct microbial communities.

In the overweight/obesity group, saliva samples showed significantly altered abundance of eleven genera compared to controls.

• Five genera showed significantly higher abundance in saliva samples of the overweight/obesity group.
• Six genera showed significantly lower levels in saliva samples of the overweight/obesity group.
• Specific genera names are not detailed in the abstract but were identified through 16S rRNA gene sequencing.

Oral mucosal plaque and dental plaque samples showed genus-level differences in the overweight/obesity group compared to controls.

• In mucosal samples, five genera exhibited increased abundance in the overweight/obesity group.
• In dental plaque samples, two genera had reduced levels in the overweight/obesity group.
• These findings indicate niche-specific microbial alterations within the oral cavity associated with overweight/obesity.

Fecal samples from the overweight/obesity group showed significantly altered abundance of ten genera compared to controls.

• Two genera displayed significantly higher abundance in fecal samples of the overweight/obesity group.
• Eight genera showed significantly lower levels in fecal samples of the overweight/obesity group.
• The greater number of genera with reduced abundance suggests broader fecal microbial depletion in overweight/obese children.

Distinct microbial taxa in both oral and fecal samples were correlated with clinical parameters including BMI and skin-fold thickness.

• Body mass index (BMI) and skin-fold thickness (SFT) were the clinical parameters examined in correlation analyses.
• Both oral and fecal microbial taxa showed correlations with these adiposity-related clinical measures.
• This association suggests a potential link between microbial composition and measures of body fat in preschool children.

Negative correlations between oral bacteria and fecal bacteria were significantly attenuated in children with overweight/obesity.

• Correlation analysis showed that oral bacteria were significantly negatively correlated with fecal bacteria in the overall sample.
• This negative oral-fecal bacterial correlation was markedly attenuated in children with overweight/obesity compared to normal-weight controls.
• This finding suggests that the oral-gut microbial axis may be disrupted in the context of childhood overweight/obesity.