Hafnia alvei is the only species of the genus Hafnia. It is foundin human and animal feces, sewage, soil, and water. H. alvei is motile. It does not ferment lactose, raffinose, sucrose, adonitol dulcitol, and inositol. It is indole and MR negative, and VP and citrate positive. Biochemical reactions are better read on incu-bation at 22°C than at 37°C. The bacteria have been isolated from abscesses, wounds, sputum, urine, blood, and from other sites, but often with other bacteria. The pathogenic role of H. alvei is yet to be established.