Characterization of the oral microbiome in the diverse South African population by PacBio HiFi sequencing.

Mounting evidence supports population-specific variation in the microbiome. This study applied PacBio HiFi 16S rRNA amplicon sequencing to profile the oral microbiome of 62 individuals (aged 18-55 years) from the four major South African population groups (Black, Coloured, Indian and White). Bioinformatics analysis was performed using QIIME2 with taxonomic classification based on the SILVA database. Across all groups, Firmicutes was the most dominant phylum (80.92%), followed by Proteobacteria (8.94%) and Bacteroidota (4.22%). A total of 236 genera and 376 species were identified. Veillonella was the most abundant genus (27.57%), followed by Streptococcus (25.08%) and Granulicatella (15.54%). Streptococcus (30.40%) and Veillonella (41.82%) were the most abundant in the Indian and Coloured populations, respectively. Significant microbiome variation was observed between groups (β-diversity, p < 0.001), highlighting distinct population-specific microbial profiles. The Coloured population exhibited the highest microbiome diversity, likely due to complex genetic makeup and diverse cultural influences. The White population displayed the lowest microbiome diversity, likely due to more uniform lifestyle patterns. Despite these differences, three bacterial species, namely, Streptococcus salivarius, Veillonella atypica, and Prevotella melaninogenica were present in the majority of individuals across the populations, suggesting a core component of the South African oral microbiome. No significant associations were observed between factors such as sex, age, diet antibiotic use, lifestyle and oral microbiome variation. Several undetermined factors, such as psychological factors, stress, level of exercise, host genetics and immunity, could have contributed to the observed diversity. Our results present the first report of oral microbiome analysis of healthy South African populations by PacBio HiFi sequencing and warrant further research to provide insight into how these differences influence health disparities and potential application in forensics. KEY POINTS: • First report of the oral microbiome of healthy South Africans by PacBio HiFi sequencing • S. salivarius, P. melaninogenica and V. atypica define South Africa's core oral microbiome • Population-specific microbiome signatures can guide forensics and health research.