Stool cultures at the ICU: get rid of it!

BACKGROUND: Stool cultures for Campylobacter, Salmonella and Shigella and/or Yersinia spp. are frequently ordered in critically ill patients with diarrhea. The aim of this study is to analyze the diagnostic yield in a large cohort of critically ill patients. Therefore, we performed a cohort study at the Department of Intensive Care Medicine of a University Hospital (11 ICUs).

RESULTS: From all patients who were admitted to the ICU between 2010 and 2015, stool cultures were taken from 2.189/36.477 (6%) patients due to diarrhea. Results of all stool cultures tested for Campylobacter, Salmonella and Shigella and/or Yersinia spp. were analyzed. Overall, 5.747 tests were performed; only six were positive (0.1%). In four of these, Campylobacter spp. were detected; diarrhea started within 48 h after ICU admission. Two patients with Salmonella spp. detection were chronic shedders. On the contrary, testing for Clostridium difficile via GDH- and toxin A/B-EIA yielded positive results in 179/2209 (8.1%) tests and revealed 144/2.189 (6.6%) patients with clinically relevant C. difficile infection.

CONCLUSIONS: Stool testing for enteric pathogens other than C. difficile should be avoided in ICU patients and is only reasonable when diarrhea commenced less than 48 h after hospital admission.