Characterization of the Gut Microbiota Composition of the Population Residing in Friuli-Venezia Giulia through Next-Generation Sequencing (NGS)

The gut microbiota is an ecological community of symbiotic and commensal microorganisms that play crucial roles in nutrient metabolism, maintaining the structural integrity of the intestinal mucosal barrier, immunomodulation, and pathogen protection. The composition of the gut microbiota varies with age, ethnicity, lifestyle, and dietary habits. Given the microbiota's growing role as a modulator of various physiological and pathological conditions, our study aimed to investigate the genetic profile of the microbiome in healthy individuals residing in the Friuli-Venezia Giulia region. We analyzed fecal swabs of 109 healthy subjects. The hypervariable V3-V4 regions of bacterial 16S rRNA were analyzed using Next Generation Sequencing (NGS) on the MiSeq system (Illumina). The relative abundance of phyla, classes, orders, families, and species was defined after normalization for the number of 16S gene copies. Firmicutes was the most represented phylum (51.1%), followed by Bacteroidetes (38.3%) and Actinobacteria (3%). At the class level, Clostridia (45.2%) and Bacteroidia (37.7%) were predominant, while Clostridiales (46.9%), Bacteroidales (26.6%), and Anaeroplasmatales (12.6%) were notable orders. Lachnospiraceae (21.9%) and Ruminococcaceae (16.2%) were the most frequent families, with Faecalibacterium prausnitzii (10.3%), Bacteroides vulgatus (4.6%), and Bacteroides dorei (3.5%) being prominent species. Each subject's alpha-diversity, enterotype, Firmicutes/Bacteroidetes ratio, gram-positive/gram-negative ratio, and individual taxa were analyzed to identify genera involved in dysbiosis. Significant associations emerged between specific taxa of microorganisms and age, gender, anti-inflammatory drugs, tobacco consumption, and allergies. This study provides valuable insights into what constitutes a "healthy intestinal microbiota". The characterization of the microbiota in the Friuli-Venezia Giulia (FVG) region lays the foundation for future research into regional variations in microbiota composition and its impact on health.