Gut microbiota markers associated with obesity and overweight in Italian adults

Abstract Purpose: The present study aims to identify distinctive signatures in the gut microbiota (GM) of overweight and obese patients (OB) recruited in Sardinia, an island in Italy.Methods: 46 stool samples from OB patients (BMI=36.6±6.0; F/M=40/6) were collected and compared to 46 normal-weight controls (BMI=21.6±2.1; F/M=41/5). Barcoded amplicon libraries for the bacterial community analysis were generated using primers targeting the V3 and V4 hypervariable regions of the bacterial 16S rRNA gene and Nextera XT index kit (Illumina, inc.). Samples were sequenced and analyzed with the Illumina MiSeq platform and the 16S metagenomics app and the MiSeq Reporter software. Results: We demonstrated that the microbial community of OB individuals was characterized by a depletion in several Bacteroidetes taxa (i.e. Flavobacteriaceae, Porphyromonadaceae, Sphingobacteriaceae, Flavobacterium, Parabacteroides, Rikenella, Pedobacter sp, Bacteroides sp). Besides, many taxa within Firmicutes were more abundant in the OB group (Lachnospiraceae, Gemellaceae, Paenibacillaceae, Streptococcaceae, Thermicanaceae, Gemella, Megamonas, Streptococcus, and Veillonella). The identified microbial patterns within Bacteroidetes were negatively correlated with body fatness, while Firmicutes taxa were positively correlated with body fatness and negatively correlated with the muscle mass or with the level of physical activity. In addition, the relative abundance of taxa within Enterobacteriaceae known for having an endotoxic activity was increased in the OB group. Conclusion: The present study extends our knowledge of the gut microbiota profiles in Italian obese and overweight patients, identifying novel taxa linking obesity and intestine.