Fermenting gram negative rod, of the Enterobacteriaceae family
Normal GI flora - most predominant gram negative bacillus
Most common cause of UTI. Also common: intra-abdominal infection/abscess, nosocomial pneumonia, bacteremia, prosthetic device infection.
Myriad other manifestations - endocarditis is very rare.
Gastroenteritis, ranging from travellers' diarrhea to invasive infection with hemolytic-uremic syndrome