When should routine stool cultures be obtained?
Stool cultures are overused in clinical practice and are often a source of misspent time and money. Bacteria that are commonly tested include Salmonella spp., Campylobacter spp., Shigella spp., and STEC. They are positive in only approximately 1.5% to 5% of samples submitted. Stool cultures are clinically useful in nonhospitalized patients who have had diarrheal illnesses lasting for more than 5 days, cases suspicious for dysentery or severe diarrhea, or in cases of outbreaks. Stool cultures should not be submitted in patients who have been hospitalized for more than 3 days.