Etiology of bloody diarrhea among patients presenting to United States emergency departments Prevalence of Escherichia coli O157 : H7 and other enteropathogens

Escherichia coli O157:H7 and other Shiga toxin-producing E. coli (STEC) inf ections have been associated with bloody diarrhea. The prevalence of entero pathogens among patients with bloody diarrhea was determined by a prospecti ve study at 11 US emergency departments. Eligible patients had bloody stool s, greater than or equal to3 loose stool samples per 24-h period, and an il lness lasting <7 days. Among 873 patients with 877 episodes of bloody diarr hea, stool samples for culture were obtained in 549 episodes (62.6%). Stool cultures were more frequently ordered for patients with fever, >10 stools/ day, and visibly bloody stools than for patients without these findings. En teropathogens were identified in 168 episodes (30.6%): Shigella (15.3%), Ca mpylobacter (6.2%), Salmonella (5.8%), STEC (2.6%), and other (1.6%). Enter opathogens were isolated during 12.5% of episodes that physicians thought w ere due to a noninfectious cause. The prevalence of STEC infection varied b y site from 0% to 6.2%. Hospital admissions resulted from 195 episodes (23. 4%). These data support recommendations that stool samples be cultured for patients with acute bloody diarrhea.