This microbe is a Gram negative rod-shaped bacterium commonly found in feces, but infrequently isolated from blood and other human clinical samples. Reports of antibiotic-resistant forms in wounds and the urinary tract in immunocompromised adults, and its recognition as an increasingly common isolate from gastrointestinal infections, are causes for growing concern about its role in disease. It was formerly known as Enteric Group 10. The rods occur singly or in pairs and can be motile by peritrichous flagella. Growth occurs optimally at 35-37 C.