# Lactobacillus-Dominated Cervical Microbiota Revealed by Long-Read 16S rRNA Sequencing: A Greek Pilot Study

## TL;DR

This study used long-read sequencing to analyze the cervical microbiota in Greek women, finding that Lactobacillus species dominate and may protect against disease.

## Contribution

The study provides a high-resolution genomic characterization of the cervical microbiota using long-read 16S rRNA sequencing in a Greek cohort.

## Key findings

- Lactobacillus iners, Lactobacillus crispatus, and Aerococcus christensenii dominated the cervical microbiota in over 75% abundance.
- Low-abundance taxa like Stenotrophomonas maltophilia and Prevotella amnii were detected, suggesting niche-specific functions.
- No HPV genotypes were detected in any of the cervical samples.

## Abstract

Background/Objectives: The vaginal microbiota constitutes a highly dynamic microbial ecosystem shaped by the distinct mucosal, hormonal, and immunological environment of the female genital tract. Accumulating evidence suggests that shifts in cervical microbial composition and function may influence host–microbe interactions and contribute to gynecological disease risk. Within this framework, the present study aimed to perform an in-depth genomic characterization of the cervical microbiota in a well-defined cohort of Greek women. The primary objective was to explore the functional microbial landscape by identifying dominant bacterial taxa, taxon-specific signatures, and potential microbial pathways implicated in cervical epithelial homeostasis, immune modulation, and disease susceptibility. Methods: Microbial genomic DNA was isolated from 60 cervical samples using the Magcore Bacterial Automated Kit and analyzed through full-length 16S rRNA gene sequencing using the Nanopore MinION™ platform, allowing high-resolution taxonomic assignment and enhanced functional inference. In parallel, cervical samples were screened for 14 HPV genotypes using a real-time PCR-based assay. Results: The cervical microbial communities were dominated by Lactobacillus iners, Lactobacillus crispatus, and Aerococcus christensenii, collectively representing over 75% of total microbial abundance and suggesting a functionally protective microbiota profile. A diverse set of low-abundance taxa—including Stenotrophomonas maltophilia, Stenotrophomonas pavanii, Acinetobacter septicus, Rhizobium spp. (Rhizobium rhizogenes, Rhizobium tropici, Rhizobium jaguaris), Prevotella amnii, Prevotella disiens, Brevibacterium casei, Fannyhessea vaginae, and Gemelliphila asaccharolytica—was also detected, potentially reflecting niche-specific metabolic functions or environmental microbial inputs. No HPV genotypes were detected in any of the cervical samples. Conclusions: This genomic profiling study underscores the functional dominance of Lactobacillus spp. within the cervical microbiota and highlights the contribution of low-abundance taxa that may participate in metabolic cross-feeding, immune signaling, or epithelial barrier modulation. Future large-scale, multi-omics studies integrating metagenomics and host transcriptomic data are warranted to validate microbial functional signatures as biomarkers or therapeutic targets for cervical health optimization.