Comparison of the oral microbial composition between healthy individuals and periodontitis patients in different oral sampling sites using 16S metagenome profilingOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study compared the oral microbiome across three sampling sites to see whether easier-to-collect samples could replace invasive sub-gingival plaque for periodontitis diagnosis. Researchers profiled saliva, supra-gingival plaque, and sub-gingival plaque. They used 16S rRNA gene sequencing of the V3-V4 hypervariable region on an Illumina MiSeq platform. Data were processed with QIIME2 and the SILVA v138 database. Alpha diversity, beta diversity, relative abundance, and LEfSe analyses compared groups and sites.
Who was studied?
The study enrolled 20 adults in South Korea: 10 healthy controls and 10 patients with severe (stage 3 or 4) periodontitis. Mean age was 31.1 years in controls and 43.8 years in patients. A total of 50 oral samples were collected: 20 saliva, 20 supra-gingival plaque, and 10 sub-gingival plaque. Sub-gingival plaque was taken only from periodontitis patients, from pockets of at least 5 mm depth. Patients had significantly higher probing depth, attachment loss, gingival index, and plaque index (p less than 0.01).
What were the most important findings?
In saliva, periodontitis patients showed significantly higher relative abundance of Porphyromonas gingivalis (3.72% vs 0%, p less than 0.05), Treponema denticola (0.59% vs 0%, p less than 0.05), and Prevotella intermedia (2.56% vs 0.01%, p less than 0.05). Haemophilus parainfluenzae fell from 23.5% to 4.6%. Saliva showed higher alpha diversity than supra-gingival plaque but no significant difference from sub-gingival plaque. In sub-gingival plaque, P. gingivalis reached 12.1% and T. denticola 4.07%. Saliva mirrored the sub-gingival profile more closely than supra-gingival plaque did.
What are the greatest implications of this study?
The findings suggest saliva could substitute for sub-gingival plaque in microbial diagnosis of periodontitis, sparing patients an uncomfortable invasive procedure. Saliva captured the red-complex pathogens and diversity of the deep pocket. The sample was small (20 subjects), and controls provided no sub-gingival sample, limiting direct comparison. Smoking and other risk factors were not analyzed in depth. Larger studies are needed before saliva-based diagnosis is adopted clinically.