Stool Cultures
Routine stool cultures for bacterial causes of diarrhea detect Campylobacter, Salmonella and Shigella. Special media to detect E. coli O157 should also be included with all stool cultures because of the serious nature of this pathogen.
Campylobacter is the most common bacterial cause of enteritis worldwide, in both developed & developing nations. Campylobacter enteritis can be associated with significant sequelae including Guillain-Barre syndrome, and can also result in bacteremia. Campylobacter is a fastidious organism & isolation from stool culture is dependent upon prompt receipt of a fresh specimen in the lab. Non-culture detection methods for Campylobacter antigen by enzyme immunoassay (EIA) are now available and detect 25% more Campylobacter isolates than culture alone.
E. coli O157 produces shiga toxin and is associated with hemorrhagic colitis and hemolytic uremic syndrome. Relatively recently, many other serotypes of shiga toxin producing E. coli have been discovered that cause similar disease. These serotypes appear to be increasing in prevalence and are not detected by routine stool cultures. Immunoassays for detection of shiga toxin are available that identify multiple serotypes and increase detection rates by 20-60%.
