Supplementary Material for: Dysbiosis of Oral Microbiota Associated with Palmoplantar Pustulosis

<b><i>Background:</i></b> Dysbiosis of oral microbiota is implicated not only in oral inflammatory lesions, but also in a variety of extraoral diseases. The etiology of palmoplantar pustulosis (PPP) remains unclear; however, it has been suggested that chronic inflammation caused by periodontopathic bacterial infection may play a role. <b><i>Objectives/Methods:</i></b> To determine whether patients with PPP have altered diversity and composition of oral microbiota, we conducted the 16S rDNA analysis using saliva samples collected from 21 outpatients with PPP and 10 healthy individuals. <b><i>Results:</i></b> We found that the proportion of bacteria in the phylum Proteobacteria was significantly lower in PPP patients (<i>p</i> = 0.025). At the genus level, patients with PPP had a significantly lower abundance of <i>Neisseria</i> (<i>p</i> = 0.014), which best accounted for the observed decrease in Proteobacteria. We also identified multiple minor genera and species that were represented at a significantly higher level in the PPP group, several of which have been associated with periodontal diseases. <b><i>Conclusion:</i></b> Our results suggest a possible link between PPP and dysbiosis of oral microbiota, particularly the lower abundance of <i>Neisseria</i>, the most predominant genus of Proteobacteria in healthy oral microbiota. Probiotics that improves oral dysbiosis may be beneficial for patients with PPP as an adjunctive therapy.