Abstract
OBJECTIVE: The oral microbiome is one of the most complex microbial ecosystems in the host. This study aimed to investigate and characterize the oral microbiome composition in Kazakhstani adolescents associated with dental caries. METHODOLOGY: The study included 312 adolescents, with 241 individuals presenting with caries and 71 caries-free, aged 12-15 years. Dental caries assessment was performed using DMFT (Decayed, missed, filled teeth) index. Oral samples were collected, and 16S rRNA (16S ribosomal ribonucleic acid) gene sequencing targeting the V3-V4 hypervariable regions on an Illumina MiSeq platform was performed to profile the microbial communities. Functional metagenomic predictions were generated using PICRUSt2 v2.5.0, using the KEGG database for bacterial pathway abundance estimation. Data analysis was conducted using Python 3.9.16 and R 4.2.2. RESULTS: The alpha diversity was insignificant, while beta diversity analysis demonstrated clear distinctions by Bray-Curtis (F=2.5, p=0.003) and weighted UniFrac distances (F=4.4, p=0.002). The Neisseria and Prevotella genera, and Gammaproteobacteria class showed significant associations with dental caries (MaAsLin2 p≤0.05, LDA≥2), stronger predictive power (AUC=0.65, F1=0.83), and higher predicted functional activity through glutathione metabolism, RNA degradation, and unsaturated fatty acid metabolism pathways. CONCLUSIONS: This study identified specific oral microbiome patterns associated with dental caries in Kazakhstani adolescents, revealing interactions between key bacterial taxa and metabolic pathways.