Oral Eikenella as a potential new biomarker of symptomatic carotid atherosclerosis

Introduction Oral microbiota dysbiosis is linked to cardiovascular disease, and oral pathogens have been detected in atherosclerotic plaques. We aimed to investigate the relationship between the oral microbiota and carotid atherosclerosis, and the occurrence of oral pathogens in plaques.Patients and methods Oral swab and saliva samples from patients with severe carotid atherosclerosis (≥50% stenosis) were compared with those from controls. The oral microbiome was analyzed by 16S rRNA amplicon sequencing targeting the V3‒V4 region. Carotid plaques were investigated for five oral bacterial species by qRT-PCR.Results Compared with controls, patients exhibited different inter-individual (beta) diversity (r = 0.02, p = 0.002), reduced intra-individual (alpha) diversity (p = 0.026) and 22 bacterial genera differed in relative abundance. Furthermore, abundances of five bacterial genera, including Eikenella, were increased in patients with recent cerebrovascular symptoms compared to asymptomatic patients. Eikenella corrodens was detected in all 30 carotid plaques.Conclusion Oral microbiota diversity and composition differ between patients with carotid atherosclerosis and controls. A higher relative abundance of the genus Eikenella in symptomatic versus asymptomatic patients and the detection of the species Eikenella corrodens in all carotid plaques, might suggest that Eikenella is important in atherogenesis and plaque instability. Oral Eikenella could possibly serve as a potential new biomarker.