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The association between oral health and systemic disease is recognized in the literature. The present study aimed to clarify the association between oral bacteria on the tongue dorsum and factors associated with oral health and systemic disease in middle-aged and elderly patients. The association between bacterial numbers, oral health status and systemic disease was preliminarily investigated in 70 patients (mean age, 69.5 years; range, 45–92 years) who visited the Department of Oral Health, Hiroshima University Hospital (Hiroshima, Japan). The bacterial 16S ribosomal RNA gene was employed to quantitate bacterial numbers using real-time polymerase chain reaction (PCR). PCR was also performed to detect the DNA of periodontal disease-related bacteria. Oral bacterial numbers were marginally negatively correlated with moisture levels on the tongue surface [Spearman's rank correlation coefficient (R)=−0.131, P=0.28). Subjects with bleeding on probing (BOP) or a ≥4 mm probing depth (PD) exhibited higher Porphyromonas gingivalis (P. gingivalis)-positive rates (50.0 and 51.1%, respectively) than those without BOP or a <4 mm PD (39.5 and 30.4%, respectively). Subjects with medical histories of hypertension, diabetes, stroke and heart disease exhibited a trend toward higher P. gingivalis-positive rates than those without such disorders. These findings indicated that the tongue moisture level may be associated with bacterial numbers on the tongue surface, while P. gingivalis on the tongue surface may be associated with systemic and periodontal diseases. Further investigation in a larger number of participants is necessary to clarify the correlation between bacterial numbers and systemic disease. [ABSTRACT FROM AUTHOR]

Due to varying positive rates of polymerase chain reaction (PCR) amplification, interpretation of conventional PCR results for non‑infectious ascites remains problematic. The present study developed a highly sensitive PCR protocol and investigated the positive rate of PCR for the 16S ribosomal (r)RNA gene in non‑infectious ascites. Following the design of a new PCR primer pair for the 16S rRNA gene (800F and 1400R), the sequences of PCR products were analyzed and the lower limit for bacterial DNA detection evaluated. The positive rate of PCR for 16S rRNA gene in non‑infectious ascites was also evaluated. PCR with the primer pair amplified the genomic DNA of 16S rRNA genes of major disease‑causing bacterial strains. Additionally, PCR with this primer pair provided highly sensitive detection of bacterial genomic DNA (lower limit, 0.1 pg of template DNA). When DNA samples isolated from ascites were used, the 16S rRNA gene was amplified independently of the presence of bacterial infection. PCR products contained the genomic DNA fragments of multiple bacterial species. Bacterial genomic DNA can be amplified from all ascitic fluids using a highly sensitive PCR protocol. Careful attention is required to interpret the results based on simple amplification of 16S rRNA gene with conventional PCR. [ABSTRACT FROM AUTHOR]

The oral microbiota are closely related to human health. Nonetheless, to the best of our knowledge, their relationship with membranous nephropathy (MN) remains unstudied. The saliva microbiota collected from 22 patients with MN and 15 healthy controls were analyzed by next-generation sequencing, and bioinformatics analysis of the 16S ribosomal RNA gene was subsequently carried out. The Chao1 and Shannon indices in patients with MN were higher than those in healthy controls. Analysis of similarities revealed that the oral microbiota in the patient group were significantly different from those in the healthy controls. At the genus level, the abundance of Alloprevotella, Granulicatella, Prevotella, Streptococcus and Prevotella_7 was markedly higher in patients with MN than in healthy controls. Six operational taxonomic units (OTUs; OTU5, OTU28, OTU9, OTU15, OTU33 and OTU38) were found to be markedly correlated with the clinical factors creatinine, proteinuria in 24 h, estimated glomerular filtration rate and systolic blood pressure. A total of 28 Kyoto Encyclopedia of Genes and Genomes pathways were obtained from the significant OTUs. The oral microbiota of patients with MN were investigated and it was found that OTU5, OTU28, OTU9, OTU15, OTU33 and OTU38 may be used as biomarkers. The present findings may assist in the diagnosis of patients with MN. [ABSTRACT FROM AUTHOR]