Oral and Gut Microbial Connectivity in Healthy Adults Revealed by Full-Length 16S rRNA Nanopore Study

Abstract

Background:
The oral cavity and gastrointestinal tract harbor distinct yet interconnected microbial ecosystems that influence host metabolism and immune homeostasis. While oral–gut microbial interactions have been implicated in disease states, baseline data describing microbial connectivity and iron-associated taxa in healthy, non-anemic adults remain limited. Advances in long-read sequencing now allow high-resolution profiling of microbial communities across anatomical niches.

Methods:
This observational study analyzed paired oral and stool samples from five healthy, non-anemic adult volunteers. Full-length 16S rRNA gene sequencing was performed using Nanopore technology to achieve high taxonomic resolution. Sequencing data underwent quality control, taxonomic assignment, and comparative analysis to evaluate site-specific microbial composition, shared taxa, and the distribution of iron-associated bacterial genera. All participant identifiers were anonymized prior to analysis.

Results:
Distinct microbial signatures were observed between oral and gut samples. The oral microbiome was dominated by genera such as Streptococcus, Veillonella, and Prevotella, whereas the gut microbiome exhibited greater diversity with enrichment of Bacteroides, Faecalibacterium, and Ruminococcus. Despite strong site specificity, a subset of bacterial genera was shared between oral and gut niches, most Just state the fact Prevotella and Fusobacterium. Several iron-associated bacterial taxa were detected across both sites, although their relative abundance differed by anatomical location. Gut samples demonstrated higher microbial richness and evenness compared to oral samples, consistent with established ecological differences.

Conclusion:
Healthy adults exhibit pronounced oral–gut microbial compartmentalization alongside limited but consistent microbial overlap. The presence of shared iron-associated taxa suggests a functional dimension to oral–gut microbial connectivity under physiological conditions. These findings establish a high-resolution baseline for healthy microbiomes and provide a reference framework for future studies investigating microbiome alterations in iron-related disorders and disease states.