A fecal sample obtained for culture was positive for E. coli (0157:H7). 

E. coli colitis has a predilection for involvement of the transverse colon and both ascending/descending colon with right-sided predominance. The location of bowel involvement may indicate the type of infectious colitis responsible. 

Typhoid fever (salmonellosis) preferably involves the cecum, ascending colon and invariably the ileum. Shigellosis predominantly affects the descending colon. Campylobacteriosis affects the small bowel and colon. 

Clinical history will often provide clues to the underlying etiology. Non-infectious causes of colitis to be considered include inflammatory bowel disease in adults, ischemic colitis in the elderly and pseudomembranous colitis.