Thesis (Ph.D.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Periodontology

Aim: Chronic hepatitis C virus (HCV) infection is an epidemic disease in Egypt. A link between the liver, gut microbiota and oral microbiota was proposed. Changes in the microbiome of the oral cavity were detected in other chronic liver diseases; suggesting it to be part of the disease pathogenesis. However, the oral microbiome was never investigated in patients having chronic HCV. Therefore, our study aimed to test the oral microbiome of patients having chronic HCV and compare it to that of healthy individuals.Methodology: We performed a case-control study where swabs from the buccal mucosa were obtained from 10 patients having chronic hepatitis C virus and 10 healthy controls; matched by age and sex. The microbiome of the samples was sequenced by 16S rRNA sequencing technology using Ion Torrent platform.Results: Samples of patients having chronic HCV infection showed higher diversity, evenness and richness of oral microbiome when compared to healthy controls. They also revealed higher abundance of Prevotella, Veillonella and Enterococcaceae at the expense of Streptococcus genus.Conclusions: Patients having chronic HCV infection have dysbiotic oral microbiome that shifts towards endotoxemia, activating pro-inflammatory pathways, inactivating anti-inflammatory pathways and reflecting intestinal permeability and bacterial translocation. The shift may be an vii active player in the chronicity of the liver disease and in the pathogenesis of HCV-associated lichen planus

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