Update: Recommendations for Diagnosis of Shiga Toxin-Producing Escherichia coli Infections by Clinical Laboratories

Shiga toxin-producing Escherichia coli (STEC) are a leading cause of bacterial enteric infections in the United States. Prompt laboratory identification of STEC strains is essential for detecting new and emerging serotypes, for effective and timely outbreak responses and control measures, for monitoring trends in disease epidemiology, and to ensure accurate diagnosis and treatment. Guidelines for laboratory identification of STEC infections by clinical laboratories were published in 2006 and 2009 (CDC, MMWR Morb. Mortal. Wkly. Rep. 55:1042-1045, 2006; MMWR Recomm. Rep. 58[RR-12], 1–14, 2009). We summarize these recent recommendations for STEC testing by clinical laboratories to emphasize the recommendation that all stools submitted for routine testing from patients with acute community-acquired diarrhea (regardless of patient age, season of the year, or presence or absence of blood in the stool) be simultaneously cultured for E. coli O157:H7 (O157 STEC) and tested with an assay that detects Shiga toxins to detect non-O157 STEC.