This is a straight rod occurring singly and in pairs. It is usually motile by peritrichous flagella. Gram reaction is negative. Gas is produced from sugars, and most strains do not produce hydrogen sulfide. It is an opportunistic pathogen commonly found in feces of man and animals without any symptoms of disease, and in water, sewage, soil, and food. Growth is at 35-37 C. If it finds its way into the urinary tract and persists, it can be responsible for infection. Evidence also is beginning to link this organism with occasional GI infections. Previously called Levinea amalonaticus, it was reclassified as a Citrobacter based on DNA hybridization studies.