Approach to the patient with infectious colitis

Abstract

Purpose of review: To provide current recommendations for evaluation and treatment of patients with infectious colitis. Infectious colitis is diagnosed in someone with diarrhea and one or more of the following: fever and/or dysentery, stools containing inflammatory markers such as leukocytes, lactoferrin, or calprotectin, or positive stool culture for an invasive or inflammatory bacterial enteropathogen including Shigella, Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli (STEC) or Clostridium difficile, or colonic inflammation by endoscopy.

Recent findings: Standard stool culture should be performed in patients with infectious colitis. Epidemiologic findings including prior international travel, shellfish-associated diarrhea, living in parasite-endemic regions may suggest the need for specialized studies of etiology. When STEC is suspected as a pathogen because only low grade or no fever is seen in a patient with acute dysentery, a competent laboratory should look for E. coli O157:H7 and Shiga toxin directly in stool.

Summary: Once laboratory diagnosis is made, pathogen-specific antimicrobial therapy should be initiated for all forms of infectious colitis other than STEC. For empiric treatment of febrile dysenteric diarrhea invasive bacterial enteropathogens (Shigella, Salmonella, and Campylobacter) should be suspected and adults may be treated empirically with 1000mg azithromycin in a single dose.