Volatile Sulfur Compounds Produced by the Anaerobic Bacteria <i>Porphyromonas</i> spp. Isolated from the Oral Cavities of Dogs

<i>Porphyromonas</i> spp. are oral anaerobic Gram-negative bacteria that form black-pigmented colonies on blood agar and produce volatile sulfur compounds (VSCs), such as hydrogen sulfide (H₂S), methyl mercaptan (CH₃SH), and dimethyl sulfide ((CH₃)₂S), which cause halitosis and the destruction of periodontal tissues. <i>P. gulae</i> is considered the main pathogen involved in periodontal disease in dogs. However, the characteristics of the VSCs produced by <i>P. gulae</i> are unknown. In the present study, VSCs were measured in 26 isolates of <i>P. gulae</i> and some isolates of the other <i>Porphyromonas</i> spp. obtained from the oral cavities of dogs with periodontal disease using an in vitro assay with an Oral Chroma^TM gas chromatograph. The results demonstrated that <i>P. gulae</i> was able to produce large amounts of H₂S and CH₃SH, and the dominant product was CH₃SH (CH₃SH/H₂S was approximately 2.2). Other <i>Porphyromonas</i> spp. that were also obtained from the oral cavities of dogs with periodontal disease indicated similar levels of production of H₂S and CH₃SH to those of <i>P. gulae</i>. It is strongly suggested that the high levels of H₂S and CH₃SH produced by <i>P. gulae</i> and other <i>Porphyromonas</i> spp. contribute to halitosis and the destruction of periodontal tissues during the progression of periodontal disease in dogs.