Metagenomic Analysis to Uncover the Subgingival and Atherosclerotic Plaque Microbiota in Patients with Coronary Artery Disease

The role of periodontal pathogens in the initiation and progression of atherosclerosis has been extensively researched, yet a precise causal mechanism has not been established. The subgingival microbiota may be a source of dissemination and may contribute to the development of atherosclerosis; hence this study attempted to characterize and compare the subgingival and atherosclerotic plaques. Plaque samples were subjected to 16S rRNA-based metagenomics to study microbiota associated with subgingival and atherosclerotic plaques collected from patients with coronary artery disease. The PCoA analysis showed that the microbiomes of subgingival plaques were highly scattered and showed a diverse microbial composition, unlike the atherosclerotic plaques that did not show evident variability in the microbial composition and formed a close distinct group. The abundance of various genera in the subgingival plaques revealed Fusobacterium (11%), Acinetobacter (13%), Veillonella (9%), and Prevotella (11%) among the top ten genera. The atherosclerotic plaques contained Acinetobacter (39%), Chryseobacterium (9%), Rhizobium (5%), and Staphylococcus (4%). All the patients examined in this study had either generalized or localized periodontitis with varying degrees of severity. The community microbiota analysis revealed that 22 bacterial genera were shared between two different plaques, with Acinetobacter being dominant. Based on the Human Oral Microbiome Database, 55% of the shared microbiota in this study have been listed as periodontal microbiota, with some of them found in increased proportions in patients with periodontitis suggesting the translocation of bacteria from the periodontal pockets into the circulation. This study provides valuable insights into the possible relationship between periodontal pathogens and atherosclerotic cardiovascular disease.