Characterization of the Oral Bacteriome of the Healthy Lewis Rat

Rodents are the most frequently utilized animals for in vivo research, and rats are the most abundant rodent used to study peri-implantitis disease and progression. However, there are very few studies available that elucidate the healthy oral microbiome of rats. The aim of this study was to characterize the healthy oral bacteriome of the male Lewis rat at two unique niches, the gums and first molar, by sequencing the 16S rDNA v1-v3 region. We collected the microbiota of 12 male Lewis rats at the toothless alveolar crest and the first molar, on both sides of the mouth. We identified an average of 20,820 sequences per sample. There were no significant differences between the rat groups or sample sites in the diversity ( or {beta}) of the bacteriome. A total of 359 amplicon sequence variants (ASVs) were identified in the bacteriome, correlating to the phyla Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Parallels exist at the genus level between human and rat oral bacteriomes, however, the overall diversity between comparable sites is lower in rats than humans. Similar findings were reached when using pooled or individual swab samples of rat mouths. This study characterizes two unique ecological niches within the healthy rat oral bacteriome and provides a baseline for comparison with future studies. IMPORTANCERats are frequently used for dental research, but little is known about their normal oral microbiota. Here, we use DNA sequence analysis to identify bacterial groups colonizing the rat mouth at the tooth surface and at the gums. This work contributes to our knowledge of bacterial diversity in the rat mouth.