This microbe is a small, coccoid-shaped Gram-negative rod. Like most Yersinia species, it is more active metabolically and motile at 25-30 C than at 35-37 C. Little gas is produced from glucose. It is nonmotile at 35-37 C and little gas is produced from glucose. It has been isolated from fresh water, fish, and sewage, and infrequently from human clinical specimens (wound and respiratory tract). Other sources include livestock, wild rodents, food, and soil.