Naoki Watanabe1 , Tomohisa Watari, and Yoshihito Otsuka Author affiliations: Author affiliation: Kameda Medical Center, Kamogawa, Japan; Current affiliation: Hirosaki University, Hirosaki, Japan.1 Cite This Article Desulfovibrio species bacteria are gram-negative, sulfate-reducing, obligately anaerobic curved or spiral rods that inhabit aquatic and soil environments, as well as the gastrointestinal tracts of humans and animals (1,2).