Management of STEC Infections

General Principles

• The Infectious Diseases Society of America (IDSA) recommends avoiding antimicrobial therapy for people with infections attributed to STEC O157 and other STEC that produce Shiga toxin 2 (or if the toxin genotype is unknown), as it may increase the risk of hemolytic uremic syndrome (HUS) 1, 2
• Several retrospective studies have noted a higher rate of HUS in patients treated with antibiotics, and in vitro data indicate that certain antimicrobial agents can increase the production of Shiga toxin 2

Treatment

• Antimicrobial therapy, including levofloxacin, should be avoided as it may increase the risk of HUS by increasing Shiga toxin production 2, 1
• Antimotility agents, like loperamide, should be avoided as they may prolong toxin exposure in the intestine 2
• Supportive care, including oral or intravenous rehydration therapy, is essential in managing STEC infections, as suggested by the IDSA 3, 4 and the CDC 4
• Isotonic fluids, such as lactated Ringer's, are recommended for rehydration in patients with STEC infection 1

Monitoring

• Frequent monitoring of hemoglobin, platelet counts, electrolytes, BUN, and creatinine is recommended, with examination of peripheral blood smear for red blood cell fragmentation if HUS is suspected 1, 3
• Leukocytosis is common in STEC infections and may be a predictor of HUS development 1

Diagnosis

• The diagnosis of Shiga toxin-2-producing E. coli infection is established without the need for fecal calprotectin, as recommended by the IDSA 3
• Patients with Shiga Toxin-Producing E. coli (STEC) infections typically present with minimal or no fever, severe abdominal cramping, and bloody diarrhea, which can help distinguish them from other causes of gastrointestinal illness 3
• The Centers for Disease Control and Prevention (CDC) recommends testing all stool specimens from patients with acute community-acquired diarrhea for STEC, regardless of the presence or absence of visible blood in stool, patient age, or season, and testing should include both O157 STEC and non-O157 STEC 4
• At least 150 STEC serotypes have been associated with human disease, with the six most common non-O157 EHEC serogroups in the United States being:

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Prevention and Control

• Implementing appropriate infection control measures is crucial to prevent transmission to others, including counseling the patient on proper hand hygiene and sanitation 1
• Standard infection control measures, such as hand hygiene, food safety precautions, and prevention of cross-contamination, should be applied to prevent the spread of EPEC and STEC infections 5
• Ensuring the safety of drinking water is also crucial in preventing the spread of EPEC and STEC infections 5
• Preventive measures include cooking ground meats thoroughly, consuming only pasteurized dairy products and juices, washing fruits and vegetables properly, practicing good hand hygiene, and preventing cross-contamination during food preparation, as recommended by the World Health Organization (WHO) 1 and the CDC 6

Complications

• STEC infections can lead to HUS, particularly in children and elderly patients, and thrombotic thrombocytopenic purpura (TTP), with STEC infections, particularly those with stx2 genes, associated with an increased risk of HUS 3, 4
• Monitoring for signs of HUS, including thrombocytopenia, hemolytic anemia, and renal failure, is crucial in patients with STEC infections, as recommended by the CDC 4
• The prognosis for typical HUS is generally good with adequate management, while atypical HUS has a recurrent course, with >50% progressing to end-stage renal disease, as reported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) 1