Gut microbiota markers associated with obesity and overweight in Italian adults

Vanessa Palmas,Roberto Cusano,Emanuela Casula,Aldo Manzin,Silvia Pisanu,Veronica Madau,Paolo Uva,Andrea Deledda,Sarah Vascellari,Fernanda Velluzzi,Andrea Loviselli

doi:10.1038/s41598-021-84928-w

Abstract

In the present study, we characterized the distinctive signatures of the gut microbiota (GM) from overweight/obese patients (OB), and normal-weight controls (NW), both of Sardinian origin. Fecal bacterial composition of 46 OB patients (BMI = 36.6 ± 6.0; F/M = 40/6) was analyzed and compared to that of 46 NW subjects (BMI = 21.6 ± 2.1; F/M = 41/5), matched for sex, age and smoking status, by using 16S rRNA gene sequencing on MiSeq Illumina platform. The gut microbial community of OB patients exhibited a significant decrease in the relative abundance of several Bacteroidetes taxa (i.e. Flavobacteriaceae, Porphyromonadaceae, Sphingobacteriaceae, Flavobacterium, Rikenella spp., Pedobacter spp., Parabacteroides spp., Bacteroides spp.) when compared to NW; instead, several Firmicutes taxa were significantly increased in the same subjects (Lachnospiraceae, Gemellaceae, Paenibacillaceae, Streptococcaceae, Thermicanaceae, Gemella, Mitsuokella, Streptococcus, Acidaminococcus spp., Eubacterium spp., Ruminococcus spp., Megamonas spp., Streptococcus, Thermicanus, Megasphaera spp. and Veillonella spp.). Correlation analysis indicated that body fatness and waist circumference negatively correlated with Bacteroidetes taxa, while Firmicutes taxa positively correlated with body fat and negatively with muscle mass and/or physical activity level. Furthermore, the relative abundance of several bacterial taxa belonging to Enterobacteriaceae family, known to exhibit endotoxic activity, was increased in the OB group compared to NW. The results extend our knowledge on the GM profiles in Italian OB, identifying novel taxa linking obesity and intestine.

Highlights

Obesity is one of the major health problems in the world due to the rapid increase in its prevalence and the emergence of metabolic co-morbidities observed since the mid-twentieth century
We characterized the distinctive features of the gut microbiota (GM) from overweight/obese patients (OB), compared to normal-weight controls (NW), both of Sardinian origin by using 16S rRNA gene sequencing on the MiSeq Illumina platform
Polysaccharides fermentation of dietary fibers by members of the Firmicutes phylum leads to the production of short-chain fatty acids (SCFAs) including acetate, propionate and butyrate, which are mostly found in the human colon[27]

Summary

Introduction

Obesity is one of the major health problems in the world due to the rapid increase in its prevalence and the emergence of metabolic co-morbidities observed since the mid-twentieth century. No statistically significant differences in the Shannon index across different BMI categories and between metabolic syndrome discordant obese patient subgroups were observed (p = 0.780 and 0.873, respectively) (see Supplementary Tables S2, S3, S4 online).

Results

Conclusion