Straight rods that are Gram negative, this bacterium does not frequently produce gas from glucose. Some strains produce urease. Growth is best at 35-37 C. It is the most pathogenic species of the genus, causing a variety of infections in hospital patients, particularly among elderly patients. Severe burns, long-term indwelling medical devices, and immunocompromised patients are factors that predispose patients to nosocomial infections by this microbe. It is most frequently recovered from stool and blood specimens, wounds, burns, and bacteremias.