The oral microbial composition and diversity affect the clinical course of palmoplantar pustulosis patients after dental focal infection treatment

Palmoplantar pustulosis (PPP) is a chronic pustular dermatosis on the palms and soles. Dental focal infections are known as the major worsening factor for PPP. Recent our study of oral microbiome demonstrated dysbiosis in PPP patients. While almost half of the PPP patients improved after treatment of dental focal infections, a certain number of patients did not improve. To investigate the oral microbial factors affecting the clinical course of PPP after treatment of dental focal infection. The oral microbiota of healthy controls (n = 10), improved (n = 7) and not-improved (n = 6) patients were analyzed by sequencing of bacterial 16S ribosomal RNA gene. The UniFrac analysis suggested the differences of oral microbiota between improved and not-improved patients. The prevalence of the phylum Proteobacteria was lower in improved patients than in not-improved patients. When the alpha microbial diversity was assessed by Shannon index, Pielou’s index and the average operational taxonomic units (OTUs), not-improved patients had a lower-diversity microbiota compared to improved patients. The degree of changes of oral microbiota after dental focal infection treatment was higher in improved patients than in not-improved patients. Six genera showed significant correlation with blood test data of PPP patients. Our findings suggested that oral microbial compositions and diversity could account for the distinct clinical course of PPP patients after treatment of dental focal infection. Oral microbiome analysis of PPP patients may provide a predictive factor for clinical responsiveness to dental focal infection treatment. •Oral microbiota of palmoplantar pustulosis patients differ depending on clinical outcome.•Patients unresponsive to focal infection treatment have lower-diversity microbiota.•Microbiota of patients responsive to focal infection treatment moved greater.