Bacteriome analysis of <i>Aggregatibacter actinomycetemcomitans</i>-JP2 genotype-associated Grade C periodontitis in Moroccan adolescentsOriginal 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 profiled the subgingival bacteriome of Grade C periodontitis linked to the highly virulent JP2 genotype of Aggregatibacter actinomycetemcomitans. Researchers compared shallow and deep pockets in cases against healthy control sites. Plaque samples were genotyped by PCR of the leukotoxin operon. Bacterial communities were profiled by 16S rRNA gene sequencing of the V1 to V3 region. The team measured diversity, differential abundance, and a Subgingival Microbial Dysbiosis Index (SMDI) to gauge overall dysbiosis.
Who was studied?
The cohort was 8 Moroccan adolescents with Grade C periodontitis, all positive for the JP2 genotype, aged about 17 years. They were compared to 13 controls without periodontitis, aged about 14 to 15 years. Subjects came from a school survey across Tiznit, Dakhla, and Tangier in Morocco. None had received periodontal treatment or antibiotics in the prior 3 months. In cases, plaque was sampled from shallow pockets (4 mm or less) and deep pockets (6 mm or more). Control plaque came from healthy sulci.
What were the most important findings?
Sequencing detected 10 phyla, 109 genera, and 308 species. Proteobacteria dominated the diseased pockets, while Firmicutes led in controls. Known periodontal pathogens were enriched in disease, including the red complex members Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Health-associated species were higher in controls. Notably, non-oral gram-negative enteric rods were abundant and nearly exclusive to cases, averaging about 30 percent of the diseased bacteriome. The dysbiosis index separated deep pockets from healthy sites with 95 percent accuracy and shallow pockets with 81 percent accuracy.
What are the greatest implications of this study?
The findings suggest JP2-genotype Grade C periodontitis shares a dysbiotic subgingival community resembling adult chronic periodontitis. Classical pathogens and overall dysbiosis, not the JP2 strain alone, characterize the diseased sites. The JP2 organism itself was low in abundance, consistent with a keystone-pathogen role that triggers dysbiosis rather than dominating it. The unexpected non-oral enteric rods warrant further study for a possible opportunistic role. Because the design is cross-sectional and small, causation cannot be inferred.