a genus of motile, peritrichous, nonsporeforming, aerobic to facultatively anaerobic bacteria (family Enterobacteriaceae) containing gram-negative rods. These organisms do not produce urease and do not grow in media containing potassium cyanide. They decarboxylate lysine, arginine, and ornithine. Lactose is generally fermented. These organisms have been isolated from a wide variety of animals, including man; they may cause gastroenteritis in man and frequently are involved in localised lesions in man and lower animals. There is a single species, arizona hinshawii, the type species.