A genus of aerobic, facultatively anaerobic bacteria containing short, motile or nonmotile, gram-negative rods. Motile cells are peritrichous. Glucose and lactose are fermented with the production of acid and gas. These organisms are found in feces; some are pathogenic to humans, causing enteritis, peritonitis, cystitis, and other disorders. It is the type genus of the family Enterobacteriaceae. The type species is Escherichia coli.