Prevalence of oral species and their association with dental plaque accumulation and periodontal inflammation in middle‑aged and older people.

species are commonly found in human oral microbiome. The aim of the present study was to understand the association of the prevalence of oral species with oral hygiene and periodontal inflammation. A total of 136 patients (median age 72 years) who visited the Hiroshima University Hospital (Hiroshima, Japan) between April 2021 and June 2023 were enrolled. Swab samples were obtained from the tongue surface. DNA from species ( and ) was detected by real-time PCR analysis. Dental plaque accumulation was observed to assess the oral hygiene condition of participants. Additionally, clinical periodontal inflammation was assessed with periodontal inflamed surface area (PISA) scores. Clinical confounding factors such as age, sex, lifestyle-related disease, remaining teeth and denture wearing between species-positive and -negative groups were adjusted with a propensity score matching method. Mann-Whitney U and χ or Fisher's exact test were employed for statistical analysis. The prevalence rate was 67.6% for oral and 83.1% for . positive participants showed significantly higher plaque control record scores (an indicator of dental plaque accumulation) than negative participants (P=0.03). Additionally, / dual-positive participants exhibited significantly higher plaque control record and PISA scores than non-dual-positive participants (P=0.01 and P=0.04, respectively). Propensity score matching was conducted in the / dual-positive group and the non-dual-positive group for adjustment of clinical factors, resulting in 51 matched patient pairs. / dual-positive participants had significantly higher plaque control record scores than non-dual-positive participants (P=0.02). The present results suggest that the prevalence of both oral and is associated with poor oral hygiene in middle-aged and older people.