Phylogenetic Analysis and Subspecies Distribution of Fusobacterium nucleatum Isolated from Interdental Plaque

Abstract

Fusobacterium nucleatum (Fn) is a bacterium that plays a significant role in oral biofilm formation, and four subspecies have been identified: Fn animalis (Fna), Fn nucleatum (Fnn), Fn polymorphum (Fnp), and Fn vincentii (Fnv). The present study aimed to isolate Fn strains from interdental plaque samples collected from 40 healthy adults, as a preliminary step in evaluating the differences in biofilm-forming abilities among the subspecies. High-resolution phylogenetic analysis was conducted using the 16S rRNA and rpoB gene sequences. Among the 80 isolates analyzed, 55 strains were classified as Fn, 35 as Fnp, 14 as Fna, and six as Fnv, whereas no Fnn strains were isolated. In addition, strains belonging to other species of the genera Fusobacterium and Leptotrichia were identified. The findings of this study provide a foundation for understanding the role of each Fn subspecies in biofilm formation. The methods established in this study can serve as valuable tools for future research on Fn and oral microbiota.