Alteration of Blood Microbiome Induced by Toothbrushing in Gingivitis Patients

Objectives: Both, number and diversity of bacteria colonizing the oral cavity are higher in gingivitis patients compared to individuals without gingivitis. The purpose of this study was to determine whether tooth brushing promotes bacterial translocation (BT) from the oral cavity into the bloodstream in gingivitis patients and whether next generation sequencing (NGS) is a suitable method to reflect the risk of BT in these patients.
Methods: Samples from ten gingivitis patients (gingival index > 2) and two healthy subjects were included in this methodical pilot project. Peripheral venous blood samples were collected from each patient, one right before (baseline) and a second sample 30 sec after tooth brushing. Teeth were brushed professionally with a powered toothbrush for 2 min. To determine the impact of tooth brushing on BT, a tongue dorsum mucosal swab sampling was taken at baseline to identify the oral microbiome. Blood samples were inoculated in 6 ml vacutainer tubes containing citrate and stored along with mucosal swabs at -80°C in order to preserve 16S rDNA until microbiome analysis by NGS (IonTorrent PGM, LifeTechnologies).
Results: The oral microbiome of the participating gingivitis patients showed an increased diversity compared to the healthy controls. BT was found in nearly all study participants but was quantitatively higher in gingivitis patients compared to healthy controls. The diversity of species detected in the blood stream after tooth brushing nearly reflected the diversity of species in the oral cavity at baseline.
Conclusions: Based on our preliminary data we conclude that patients with gingivitis have a high risk of BT when tooth brushing. NGS is a suitable method to quanti- and qualitatively reflect the impact of tooth brushing on BT as it allows for the detection and identification of the majority of the bacteria in the oral cavity and the bloodstream. Further studies are warranted in order to assess whether NGS may be a viable method for the early detection of disseminating infections.